Exposure mask, method for manufacturing the mask, and exposure method

ABSTRACT

As shown in FIG.  2 , a multi-layer structured exposure mask  1  of this embodiment is provided with a frame  20  made of glass, a silicon plate  15  provided on an under surface of the frame  20 , a heat absorption mask  16  provided on an under surface of the silicon plate  15 , a silicon plate  11  provided on an under surface of the heat absorption mask  16  and a stencil mask  14  provided on an under surface of the silicon plate  11 . The stencil mask  14  is made up of a silicon substrate and is provided with a slit-shaped patterning opening  14   a  to form a resist pattern. The heat absorption mask  16  is made up of a silicon substrate coated with an SiN film and is provided with slit-shaped openings  16   a  shaped in almost the same way as the patterning openings  14   a  of the stencil mask  14 . The opening  16   a  is shaped in such a size that will not block electron beams necessary to form a resist pattern as shown in FIG.  3 ( a ). That is, a size of the opening  16   a  is equal to a size of the patterning opening  14   a  or a size of the opening  16   a  is a little larger Furthermore, the multi-layer structured exposure mask  1  of this embodiment is provided with a large opening  20   a  that penetrates the frame  20  and silicon plate  15  and exposes the area of the upper surface of the heat absorption mask  16  in which the openings  16   a  are formed. Furthermore, the multi-layer structured exposure mask  1  of this embodiment is provided with a hollow section  11   a  that penetrates the silicon plate  11  and exposes the area of the under surface of the heat absorption mask  16  in which the openings  16   a  are formed and the area of the upper surface of the stencil mask  14  in which the patterning openings  14   a  are formed. In the multi-layer structured exposure mask  1  of this embodiment, the patterning openings  14   a  of the stencil mask  14  and the openings  16   a  of the heat absorption mask  16  are aligned in the horizontal direction as shown in FIG.  3 ( a ).

TECHNICAL FIELD

[0001] The present invention relates to a charged particle beam exposuremask and X-ray exposure mask in a process of manufacturing an LSI, etc.

BACKGROUND ART

[0002] In line with miniaturization of patterns of LSI elements, thereis a demand for a new exposure technology. A method for exposure toX-rays, electron beams or ion beams used in recent years uses a thinstencil mask with openings corresponding to patterns of their respectiveLSI elements.

[0003] According to a conventional electron beam exposure apparatus, aresist, which is applied to a silicon wafer and photosensitive toelectron beams, is irradiated with electron beams through an exposuremask. At this time, the resist in an area corresponding to an openingprovided in an exposure mask causes a photoreaction due to electronbeams, which have passed through the opening.

[0004] “Photoreaction” is a term indicating a physical or chemicalchange in a matter that occurs when light beams or X-rays act on thematter, and in the present Specification, it is also used as a termindicating a physical or chemical change in a matter that occurs whenelectron beams or ion beams act on the matter. That is, the term“photoreaction” in the present Specification indicates a physical orchemical change in a matter that occurs when radiation acts on thematter.

[0005]FIG. 26 is a cross-sectional view of a conventional electron beamexposure mask. As shown in FIG. 26, an electron beam exposure mask 51 isconstructed of a frame 20 made of glass, etc. a silicon plate 11provided on the under surface of the frame 20 and a stencil mask 14provided on the under surface of the silicon plate 11. The stencil mask14 is formed of a silicon plate coated with SiC or diamond, etc. andprovided with patterning openings 14 a to form resist patterns.Furthermore, the electron beam exposure mask 51 is provided with a largeopening 20 a, which penetrates the frame 20 and silicon plate 11 andexposes the area of the upper surface of the stencil mask 14 in whichthe patterning openings 14 a are formed.

[0006]FIG. 27 is a cross-sectional view of the X-ray exposure mask 51used for a conventional X-ray exposure apparatus. As shown in FIG. 27,an X-ray exposure mask 52 is constructed of a frame 20 made of glass,etc., a silicon plate 11 provided on the under surface of the frame 20,a membrane 12 provided on the under surface of the silicon plate 11 andan X-ray shielding metal film 13 provided on the under surface of themembrane 12. The membrane 12 is formed of SiC or diamond, etc. and theX-ray shielding metal film 13 is provided with patterning openings 13 athat penetrate the X-ray shielding metal film 13 to form resistpatterns. Furthermore, the X-ray exposure mask 52 is provided with alarge opening 20 a, which penetrates the frame 20 and silicon plate 11and exposes the area of the upper surface of the membrane 12 locatedabove the area in which the patterning openings 13 a of the X-rayshielding metal film 13 are formed.

[0007] In the case where a resist 62 is irradiated with electron beamsusing the conventional electron beam exposure mask 51, if anacceleration voltage for electron beams is small, it is not possible tocause a photoreaction of the resist in the area irradiated with electronbeams completely. That is, the surface of the resist of the areairradiated with electron beams causes a photoreaction, but it isdifficult to expose the entire resist in the depth direction of the areairradiated with electron beams. To initiate the photoreaction over theentire resist in the film thickness direction of the area irradiatedwith electron beams requires the acceleration voltage of electron beamsto be increased.

[0008] However, the energy of accelerated electrons increases as theacceleration voltage increases. When electrons with such high energycollide with the stencil mask 14 of the exposure mask 51, the stencilmask 14 generates heat and expands. This deforms the stencil mask 14.This causes a problem such as preventing the resist from being subjectto a photoreaction according to the patterning openings 14 a provided onthe stencil mask 14.

[0009] The same applies to a case where an X-ray photoresist is exposedto X-rays using the conventional X-ray exposure mask 52. When irradiatedwith strong X-rays such as synchrotron radiation (hereinafter referredto as “SOR light”), the membrane 12 and X-ray shielding metal film 13are deformed by expansion as in the case of heat generation withelectron beams.

DISCLOSURE OF THE INVENTION

[0010] The present invention has been achieved to solve the problemsdescribed above and it is an object of the present invention to providean exposure mask with reduced deformation due to heat generation.

[0011] The exposure mask of the present invention includes a patterningmask having an opening and at least one heat absorption mask having anopening and placed above the patterning mask apart from the patterningmask and the opening of the patterning mask is aligned with the openingof the heat absorption mask.

[0012] According to the exposure mask of the present invention, the heatabsorption mask blocks most of radiation irradiated onto the patterningmask. This suppresses heat generation of the patterning mask due toradiation. Furthermore, since the heat absorption mask is placed apartfrom the patterning mask, heat generated at the heat absorption mask isnot transmitted to the patterning mask. This suppresses deformation bythermal expansion of the patterning mask.

[0013] It is preferable that the size of the opening of the heatabsorption mask is greater than or equals to that of the opening of thepatterning mask.

[0014] This prevents the heat absorption mask from blocking the openingof the patterning mask.

[0015] The openings of the heat absorption mask and patterning mask maybe slit-shaped and the width of the opening of the heat absorption maskmay be greater than or equal to the width of the opening of thepatterning mask.

[0016] It is preferable that thermal conductivity of the heat absorptionmask is greater than that of the patterning mask.

[0017] This allows the heat absorption mask to absorb heat efficiently.

[0018] It is preferable that a plurality of the heat absorption masks isprovided and the openings of the respective heat absorption masks arealigned with the opening of the patterning mask.

[0019] This increases the efficiency of heat absorption by a pluralityof the heat absorption masks.

[0020] It is preferable that the thickness of the heat absorption maskis greater than the thickness of the patterning mask.

[0021] This increases thermal conductivity of the heat absorption maskand allows the heat absorption mask to absorb heat efficiently.

[0022] The patterning mask and heat absorption mask may be made of thesame material.

[0023] It is preferable that the exposure mask further includes a metalcover having an opening larger than the opening of the heat absorptionmask, and the metal cover is placed above the heat absorption mask.

[0024] This allows the metal cover to absorb heat.

[0025] An alignment opening may be formed on the patterning mask and anopening in a shape different from the alignment opening and larger thanthe alignment opening may be formed in an area of the heat absorptionmasks located right above the alignment opening.

[0026] It is also possible to adopt a configuration further including asupport for supporting the edges of the patterning mask and the heatabsorption mask, and both the patterning mask and the heat absorptionmask are placed either above or below the support.

[0027] It is also possible to adopt a configuration further including asupport for supporting the edges of the patterning mask and the heatabsorption mask, and the patterning mask and the heat absorption maskare placed in such a way that the support is inserted between thepatterning mask and the heat absorption mask.

[0028] It is preferable that the support further includes a concavesection and the heat absorption mask is engaged with the concave sectionand is positioned in the concave section.

[0029] This securely fixes the heat absorption mask and makes it easierto exactly align the opening of the heat absorption mask with theopening of the patterning mask.

[0030] It is preferable that the support further includes a concavesection and the patterning mask is engaged with the concave section andis positioned in the concave section.

[0031] This securely fixes the patterning mask and makes it easier toexactly align the opening of the heat absorption mask with the openingof the patterning mask.

[0032] It is also possible to adopt a configuration including a hollowsection between the patterning mask and heat absorption mask formed byetching a member between the patterning mask and heat absorption mask.

[0033] It is also possible to provide a membrane on the upper surface ofthe patterning mask.

[0034] The exposure method of the present invention is an exposuremethod for irradiating charged particles using an exposure maskincluding a patterning mask having an opening and at least one heatabsorption mask having an opening and placed above the patterning maskapart from the patterning mask with the opening of the patterning maskaligned with the opening of the heat absorption mask, characterized inthat the charged particles are irradiated at an acceleration voltage of10 keV or above.

[0035] According to the exposure mask used in the exposure method of thepresent invention, the heat absorption mask blocks most of chargedparticles irradiated onto the patterning mask out of the chargedparticles accelerated at an acceleration voltage of 10 keV or above.This suppresses heat generation of the patterning mask due toirradiation of charged particles. Since the heat absorption mask is alsoplaced apart from the patterning mask, the heat generated from the heatabsorption mask is not transmitted to the patterning mask. Therefore,deformation by thermal expansion of the patterning mask is suppressed.

[0036] The exposure method of the present invention even in aconfiguration with charged particles irradiated at an accelerationvoltage of 50 keV or above suppresses deformation by thermal expansionof the patterning mask.

[0037] It is also possible to adopt a configuration using anotherexposure mask including a patterning mask having an opening and at leastone heat absorption mask having an opening and placed above thepatterning mask apart from the patterning mask with the opening of thepatterning mask aligned with the opening of the heat absorption mask,and in that the opening pattern of the patterning mask of the exposuremask is different from the opening pattern of the patterning mask of theother exposure mask.

[0038] The exposure method of the present invention is an exposuremethod for irradiating X-rays using an exposure mask including apatterning mask having an opening, at least one heat absorption maskhaving an opening and placed above the patterning mask apart from thepatterning mask and a membrane for supporting the pattering mask, withthe opening of the patterning mask aligned with the opening of the heatabsorption mask, characterized in that the patterning mask is formed ofsuch a material as to prevent X-rays from penetrating.

[0039] According to the exposure mask used in the exposure method of thepresent invention, the heat absorption mask blocks most of X-raysirradiated onto the patterning mask. This suppresses heat generation ofthe patterning mask due to irradiation with X-rays. Furthermore, sincethe heat absorption mask is placed apart from the patterning mask, heatgenerated at the heat absorption mask is not transmitted to thepatterning mask. This suppresses deformation of the patterning mask bythermal expansion.

[0040] Deformation of the patterning mask by thermal expansion can alsobe suppressed even using SOR-X-rays as X-rays.

[0041] It is also possible to adopt a configuration using anotherexposure mask including a patterning mask having an opening, at leastone heat absorption mask having an opening and placed above thepatterning mask apart from the patterning mask and a membrane forsupporting the pattering mask, with the opening of the patterning maskaligned with the opening of the heat absorption mask and with thepatterning mask formed of such a material as to prevent X-rays frompenetrating, and in that the opening pattern of the patterning mask ofthe exposure mask is different from the opening pattern of thepatterning mask of the other exposure mask.

[0042] The method for manufacturing an exposure mask of the presentinvention includes a step (a) of preparing a patterning mask having anopening and a heat absorption mask having an opening in almost the samepattern as the opening pattern of the patterning mask, and a step (b) ofaligning the opening of the patterning mask with the opening of the beatabsorption mask.

[0043] This provides an exposure mask with reduced deformation of thepatterning mask by thermal expansion.

[0044] The patterning mask may be formed of a laminated film of amembrane and an X-ray shielding material.

[0045] The method for manufacturing an exposure mask of the presentinvention includes a step (a) of preparing a heat absorption mask havingan opening, a step (b) of placing a patterning mask substrate below theheat absorption mask, a step (c) of stacking a resist on the undersurface of the patterning mask substrate, a step (d) of patterning theresist by irradiating radiation penetrating the patterning masksubstrate onto the resist using the heat absorption mask as the mask,and a step (e) of forming a patterning mask having an opening by etchingthe patterning mask substrate using the resist as the mask.

[0046] This provides an exposure mask with reduced deformation of thepatterning mask by thermal expansion.

[0047] In the process (b), it is also possible to insert a supportbetween the heat absorption mask and the patterning mask substrate.

[0048] The method for manufacturing an exposure mask of the presentinvention includes a step (a) of preparing a heat absorption mask havingan opening, a step (b) of providing a plate on the under surface of theheat absorption mask, a step (c) of providing the patterning masksubstrate on the under surface of the plate, a step (d) of forming apatterning mask having an opening by etching the plate and thepatterning mask substrate using the heat absorption mask as the mask,and a step (e) of removing a part of the plate located in an area inwhich the openings of the heat absorption mask and patterning mask areformed.

[0049] This provides an exposure mask with reduced deformation of thepatterning mask by thermal expansion.

[0050] In the step (e), it is preferable that the material making up theplate has a higher etching speed than the heat absorption mask and thepatterning mask substrate.

[0051] This makes it possible to easily form a hollow section betweenthe patterning mask and heat absorption mask without any damage due toetching to the patterning mask and heat absorption mask.

[0052] The method for manufacturing an exposure mask of the presentinvention includes a step (a) of placing a heat absorption mask havingan opening above the patterning mask substrate on the upper surface ofwhich a resist is formed, a step (b) of patterning the resist using theheat absorption mask as the mask, and a step (c) of forming a patterningmask having an opening by etching the patterning mask substrate usingthe resist as the mask.

[0053] This provides an exposure mask with reduced deformation of thepatterning mask by thermal expansion.

[0054] In the step (a), it is also possible to place the heat absorptionmask above the patterning mask substrate after forming the resist on theupper surface of the patterning mask substrate.

[0055] In the step (a), it is also possible to place a patterning masksubstrate on the upper surface of which a resist is formed beforehandbelow the heat absorption mask after placing the heat absorption mask.

[0056] In the step (a), it is also possible to adopt a configurationthat a support is placed to support the edges of the patterning masksubstrate and the heat absorption mask and the heat absorption mask isengaged with the support.

[0057] The method for manufacturing an exposure mask of the presentinvention includes a step (a) of placing a patterning mask having anopening above a heat absorption mask substrate on the upper surface ofwhich a resist is formed, a step (b) of patterning the resist using thepatterning mask as the mask, a step (c) of placing the heat absorptionmask substrate above the patterning mask, and a step (d) of forming aheat absorption mask having an opening by etching the heat absorptionmask substrate using the resist as the mask.

[0058] This provides an exposure mask with reduced deformation of thepatterning mask by thermal expansion.

[0059] In the step (a), it is also possible to place the patterning maskabove the heat absorption mask after forming the resist on the uppersurface of the heat absorption mask substrate.

[0060] In the step (a), it is also possible to place the heat absorptionmask substrate on the upper surface of which a resist is formedbeforehand below the patterning mask after placing the patterning mask.

[0061] It is also possible to adopt a configuration wherein a support isplaced to support the edges of the patterning mask and the heatabsorption mask substrate, the patterning mask is engaged with thesupport, and in the step (c), the heat absorption mask substrate isengaged with the support.

[0062] It is also possible to adopt a configuration repeating the steps(b) and (c).

[0063] A step (f) of placing a metal cover having an opening larger thanthe opening of the heat absorption mask above the heat absorption maskmay be further included after the step (d).

[0064] The exposure mask manufacturing method of the present inventionincludes a step (a) of placing a patterning mask having an opening abovethe heat absorption mask substrate on the upper surface of which aresist is formed, a step (b) of patterning the resist using thepatterning mask as the mask, a step (c) of forming a heat absorptionmask having an opening by etching the heat absorption mask substrateusing the resist as the mask, and a step (d) of placing the heatabsorption mask above the patterning mask.

[0065] This provides an exposure mask with reduce deformation of thepatterning mask by thermal expansion.

[0066] In the step (a), it is also possible to place the patterning maskabove the heat absorption mask substrate after forming a resist on theupper surface of the heat absorption mask.

[0067] In the step (a), it is also possible to place the heat absorptionmask substrate on the upper surface of which a resist is formedbeforehand below the patterning mask after placing the patterning mask.

[0068] It is also possible to adopt a configuration that in the step(a), a support is placed to support the edges of the patterning mask andthe heat absorption mask substrate, the patterning mask is engaged within the support, and in the step (d), the heat absorption mask is engagedwith in the support.

[0069] It is also possible to adopt a configuration repeating the steps(b) and (c).

[0070] It is also possible to adopt a configuration that a step (f) ofplacing a metal cover having an opening larger than the openings of theheat absorption mask above the heat absorption mask is further includedafter the step (d).

BRIEF DESCRIPTION OF THE DRAWINGS

[0071]FIG. 1 is a cross-sectional view showing a configuration of anelectron beam exposure apparatus using electron beams as a light source(hereinafter referred to as “EB exposure apparatus”).

[0072]FIG. 2 is a cross-sectional view showing a configuration of amulti-layer structured exposure mask according to Embodiment 1.

[0073]FIG. 3(a) is a top view showing a configuration of the multi-layerstructured exposure mask according to Embodiment 1.

[0074]FIG. 3(b) is an enlarged view of a part encircled with a circle Cshown in FIG. 3(a).

[0075]FIG. 4 is a process cross-sectional view showing a method formanufacturing the multi-layer structured exposure mask according toEmbodiment 1.

[0076]FIG. 5 is another process cross-sectional view showing the methodfor manufacturing the multi-layer structured exposure mask according toEmbodiment 1.

[0077]FIG. 6 is another process cross-sectional view showing the methodfor manufacturing the multi-layer structured exposure mask according toEmbodiment 1.

[0078]FIG. 7 is a cross-sectional view showing a configuration of amulti-layer structured exposure mask according to Embodiment 2.

[0079]FIG. 8 is a process cross-sectional view showing a method formanufacturing the multi-layer structured exposure mask according toEmbodiment 2.

[0080]FIG. 9 is another process cross-sectional view showing the methodfor manufacturing the multi-layer structured exposure mask according toEmbodiment 2.

[0081]FIG. 10 is a cross-sectional view showing a configuration of amulti-layer structured exposure mask according to Embodiment 3.

[0082]FIG. 11 is another process cross-sectional view showing the methodfor manufacturing the multi-layer structured exposure mask according toEmbodiment 3.

[0083]FIG. 12 is a cross-sectional view showing a configuration of amulti-layer structured exposure mask according to Embodiment 4.

[0084]FIG. 13 is a process cross-sectional view showing the method formanufacturing the multi-layer structured exposure mask according toEmbodiment 4.

[0085]FIG. 14 is another process cross-sectional view showing the methodfor manufacturing the multi-layer structured exposure mask according toEmbodiment 4.

[0086]FIG. 15 is a cross-sectional view of a multi-layer structuredexposure mask according to Embodiment 5.

[0087]FIG. 16 is a top view of the multi-layer structured exposure maskaccording to Embodiment 5.

[0088]FIG. 17 is a process cross-sectional view showing a method formanufacturing the multi-layer structured exposure mask according toEmbodiment 5.

[0089]FIG. 18 is a cross-sectional view showing a configuration of amulti-layer structured exposure mask according to Embodiment 6.

[0090]FIG. 19 is a process cross-sectional view showing a method formanufacturing the multi-layer structured exposure mask according toEmbodiment 6.

[0091]FIG. 20 is a cross-sectional view showing a configuration of amulti-layer structured exposure mask according to Embodiment 7.

[0092]FIG. 21 is a top view showing the configuration of the multi-layerstructured exposure mask according to Embodiment 7.

[0093]FIG. 22 is a process cross-sectional view showing a method formanufacturing the multi-layer structured exposure mask according toEmbodiment 7.

[0094]FIG. 23 illustrates an exposure method using a plurality ofexposure masks.

[0095]FIG. 24 is an enlarged view of an alignment opening formed on amulti-layer structured exposure mask.

[0096]FIG. 25 is an enlarged view of another alignment opening formed ona multi-layer structured exposure mask.

[0097]FIG. 26 is a cross-sectional view of a conventional electron beamexposure mask.

[0098]FIG. 27 is a cross-sectional view of an X-ray exposure mask usedfor a conventional X-ray exposure apparatus.

BEST MODE FOR CARRYING OUT THE INVENTION

[0099] With reference now to the attached drawings, embodiments of thepresent invention will be explained below. For simplicity, componentscommon to the embodiments are assigned the same reference numerals.

Embodiment 1

[0100] This embodiment will be explained with reference to FIG. 1. FIG.1 is a cross-sectional view showing a configuration of an electron beamexposure apparatus using electron beams as a light source (hereinafterreferred to as “EB exposure apparatus”).

Configuration of EB Exposure Apparatus

[0101] As shown in FIG. 1, an EB exposure apparatus 100 is provided withan electron gun 31, a beam extracting electrode 32, an electron beamforming aperture 33, a charged beam focusing electromagnetic fieldgenerator 34, a first main deflector 36, a second main deflector 37, afine adjustment deflector 38 and a multi-layer structured exposure mask1.

[0102] When an acceleration voltage is applied at the beam extractingelectrode 32, electron beams are extracted from the electron gun 31. Theelectron beams extracted from the electron gun 31 are converted toshaped electron beams by the electron beam forming aperture 33.

[0103] Then, the electron beams pass through an electromagnetic field ofthe charged beam focusing electromagnetic field generator 34 provided toprevent the electron beams from scattering. To move the irradiation areaof the electron beams, the first main deflector 36, the second maindeflector 37 and the fine adjustment deflector 38 deflect the electronbeams. The first main deflector 36 deflects the electron beams up to adesired position and the second main deflector 37 inversely deflects theelectron beams so that the electron beams are vertically irradiated ontothe surface of a silicon wafer 61. The fine adjustment deflector 38adjusts deflection in detail.

[0104] Then, the electron beams pass through the patterning openingprovided on the multi-layer structured exposure mask 1 and areirradiated onto an area of a resist 62 applied to the silicon wafer 61corresponding to the patterning opening.

Configuration of Multi-layer Structured Exposure Mask

[0105] Then, the multi-layer structured exposure mask 1 of thisembodiment will be explained with reference to FIG. 2 and FIG. 3. FIG. 2is a cross-sectional view of the multi-layer structured exposure mask 1according to this embodiment. FIG. 3(a) is a top view of the multi-layerstructured exposure mask 1 according to this embodiment and thesectional view along line III-III in the drawing corresponds to FIG. 2.FIG. 3(b) is an enlarged view of a part encircled with a circle C shownin FIG. 3(a).

[0106] As shown in FIG. 2, the multi-layer structured exposure mask 1 ofthis embodiment is provided with a frame 20 made of glass, a siliconplate 15 provided on the under surface of the frame 20, a heatabsorption mask 16 provided on the under surface of the silicon plate15, a silicon plate 11 provided on the under surface of the heatabsorption mask 16 and a stencil mask 14 provided on the under surfaceof the silicon plate 11.

[0107] The stencil mask 14 is made up of a silicon substrate and isprovided with a slit-shaped patterning openings 14 a to form resistpatterns.

[0108] The heat absorption mask 16 is made up of a silicon substratecoated with an SiN film and is provided with slit-shaped openings 16 ashaped almost in the same way as the patterning openings 14 a of thestencil mask 14. The opening 16 a is shaped in a size that will notblock electron beams necessary to form a resist pattern as shown in FIG.3(a). That is, the size of the opening 16 a is equal to the size of thepatterning opening 14 a or the size of the opening 16 a is a littlelarger.

[0109] Furthermore, the multi-layer structured exposure mask 1 of thisembodiment is provided with a large opening 20 a that penetrates theframe 20 and silicon plate 15 and exposes the areas of the upper surfaceof the heat absorption mask 16 in which the openings 16 a are formed.

[0110] Furthermore, the multi-layer structured exposure mask 1 of thisembodiment of this embodiment is provided with a hollow section 11 a,which penetrates the silicon plate 11 and exposes an area of the undersurface of the heat absorption mask 16 in which the patterning openings16 a are formed and an area of the upper surface of the stencil mask 14in which the patterning openings 14 a are formed.

[0111] In the multi-layer structured exposure mask 1 of this embodiment,the patterning openings 14 a of the stencil mask 14 are aligned with theopenings 16 a of the heat absorption mask 16 in the horizontal directionas shown in FIG. 3(a). In the multi-layer structured exposure mask 1 ofthis embodiment of the EB exposure apparatus 100, the frame 20 is set insuch a way as to face the electron gun 31. That is, electron beams enterthe large opening 20 a from the direction indicated by an arrow A shownin FIG. 2.

[0112] Unlike the conventional exposure mask, the multi-layer structuredexposure mask 1 of this embodiment is provided with the heat absorptionmask 16. The heat absorption mask 16 has a high heat absorption rate andremoves electron beams unnecessary to form a resist pattern out ofelectron beams irradiated onto the multi-layer structured exposure mask1. This suppresses deformation of the stencil mask 14 due to thermalexpansion and makes it possible to form more accurate resist patterns.

[0113] As shown in FIG. 3(a), the heat absorption mask 16 is providedwith openings 16 a of a size that will not block electron beamsnecessary to form resist patterns. That is, the size of the opening 16ais equal to the size of the patterning opening 14 a or the size of theopening 16 a is a little larger. Especially, it is preferable that thesize of the opening 16 a be 150% of the size of the pattering opening 14a or smaller. When the multi-layer structured exposure mask 1 of thisembodiment is used for an application where not so high precision in thelength direction of the patterning openings 14 a is required (forexample, formation of a wiring pattern, etc.), the openings 16 a can beshorter than the patterning openings 14 a.

[0114] In this embodiment, one heat absorption mask 16 made up of asilicon substrate coated with an SiN film or tungsten film is providedand the thickness of the heat absorption mask 16 is 2 μm and the widthof the opening 16 a is 60 nm. The thickness of the stencil mask 14 is0.5 μm and the width of the patterning opening 14 a is 50 nm. That is,the aspect ratio of the patterning opening 14 a is 10.

[0115] The width and length of the opening 16 a of the heat absorptionmask 16 are a little larger than the width and length of the patterningopening 14 a of the stencil mask 14 and the heat absorption mask 16 isaligned with stencil mask 14 so that the heat absorption mask 16 doesnot block the patterning opening 14 a of the stencil mask 14 whenelectron beams enter.

[0116]FIG. 3(b) is an enlarged view of a part encircled with a circle Cshown in FIG. 3(a). As shown in FIG. 3(b), the patterning opening 14 a(50 nm in width) of the stencil mask 14 indicated by broken line appearsin the opening 16 a (60 nm in width) of the heat absorption mask 16.That is, the stencil mask 14 is almost blocked by the heat absorptionmask 16. For this reason, most of electron beams which do not contributeto the formation of a resist pattern out of electron beams irradiatedonto the exposure mask are blocked by the heat absorption mask 16 andalmost no electron beams are irradiated onto the stencil mask 14.Therefore, the heat absorption mask 16 generates heat, but the stencilmask 14 generates almost no heat. This suppresses or preventsdeformation of the stencil mask 14.

[0117] Furthermore, as shown in FIG. 2, the heat absorption mask 16 andstencil mask 14 are separated by the hollow section 11 a and do notdirectly touch each other. Japanese Patent Laid-Open No. 2000-188254specification discloses a case where no hollow section 11 a is provided.Unlike this case, almost none of heat generated in the heat absorptionmask 16 is transmitted to the stencil mask 14 but dissipated to theoutside through the silicon plate 15 and frame 20. This suppresses orprevents deformation of the silicon mask 14.

[0118] In this embodiment, the thickness of the stencil mask 14 isdifferent from that of the heat absorption mask 16 and the thickness ofthe stencil mask 14 (0.5 μm) is smaller than that of the heat absorptionmask 16 (2 μm). This is because it is preferable that the thickness ofthe stencil mask 14 be smaller when workability for forming thepatterning opening 14 a with high accuracy is taken into account and thethickness of the heat absorption mask 16 be greater when thermalconductivity is taken into account.

[0119] As described above, the multi-layer structured exposure mask 1 ofthis embodiment is provided with at least one heat absorption mask 16 toprotect the stencil mask 14. This suppresses or prevents deformation ofthe stencil mask 14 when performing exposure of electron beams at a highacceleration voltage or with a high current, etc. using the multi-layerstructured exposure mask 1 of this embodiment, and makes it possible toform resist patterns accurately matching the patterning openings 14 a.

[0120] The multi-layer structured exposure mask of this embodimentdisplays an outstanding effect especially when a high accelerationvoltage rather than a low acceleration voltage is used, or morespecifically, when electron beams at 10 keV or higher or more preferably50 keV or higher are used.

[0121] This embodiment has described the case where the multi-layerstructured exposure mask 1 is used at the EB exposure apparatus, but thepresent invention is not limited to this. The multi-layer structuredexposure mask 1 of this embodiment is ideally applicable to a chargedparticle beam exposure apparatus such as an ion beam exposure apparatus.

Manufacturing Method

[0122] Then, the method for manufacturing the multi-layer structuredexposure mask 1 of this embodiment will be explained with reference toFIG. 4 to FIG. 6. According to this embodiment, any one of the followingmethods 1 to 3 can be used. FIG. 4 to FIG. 6 are process cross-sectionalviews showing the method for manufacturing the multi-layer structuredexposure mask 1 of this embodiment and correspond to the methods 1 to 3shown below respectively.

Method 1

[0123] First, in the process shown in FIG. 4(a), the frame 20 made ofglass and having a large opening, the silicon plate 15 having a largeopening as large as the large opening of the frame 20 and the heatabsorption mask 16 having openings 16 a formed in almost the samepattern as the pattering openings 14 a provided for the stencil mask 14,which will be described later are prepared. More specifically, a heatabsorption mask plate (SiN film) is formed on the under surface of thesilicon plate 15 using a CVD method, etc. Then, the heat absorption mask16 is formed by patterning the openings 16 a that penetrate the heatabsorption mask plate. Then, a large opening is formed in the siliconplate 15 in such a way that the openings 16 a of the heat absorptionmask 16 are exposed. Then, the silicon plate 15 provided with the heatabsorption mask 16 obtained is pasted onto the under surface of theframe 20. At this time, alignment is performed in such a way that thelarge opening of the frame 20 is aligned with the large opening of thesilicon plate 15 to form the large opening 20 a.

[0124] Then, in the process shown in FIG. 4(b), the silicon plate 11provided with a large opening and the stencil mask 14 provided with thepatterning openings 14 a to form a resist pattern are prepared. Morespecifically, the silicon plate 11 on the under surface of which asilicon oxide film is formed is prepared first and a stencil mask plate(Si film) is formed on the oxide film using a CVD method, etc. Then, thestencil mask 14 is formed by forming the patterning openings 14 a thatpenetrate the stencil mask plate. Then, a large opening is formed in thesilicon plate 11 in such a way that the patterning openings 14 a of thestencil mask 14 are exposed.

[0125] Then, in the process shown in FIG. 4(c), the under surface of theheat absorption mask 16 on the upper surface of which the frame 20 andsilicon plate 15 obtained in the process shown in FIG. 4(a) are providedis pasted to the upper surface of the silicon plate 11 on the undersurface of which the stencil mask 14 is provided. At this time, theopenings 16 a of the heat absorption mask 16 and the patterning openings14 a of the stencil mask 14 are aligned in the horizontal direction asshown in FIG. 3(a). In the present Specification, alignment in thehorizontal direction refers to making the openings 16 a almost matchwith patterning openings 14 a viewed from above (viewed from theirradiation direction of electron beams).

[0126] The multi-layer structured exposure mask 1 is obtained in theprocesses.

[0127] This method uses either an anode junction or an adhesive as thetechnique for pasting the frame 20, silicon plate 15, heat absorptionmask 16, silicon plate 11 and stencil mask 14 to each other.

Method 2

[0128] First, in the process shown in FIG. 5(a), the frame 20 made ofglass and having a large opening, the silicon plate 15 having a largeopening as large as the large opening of the frame 20 and the heatabsorption mask 16 having openings 16 a formed in almost the samepattern as the pattering openings 14 a provided for the stencil mask 14,which will be described later are prepared. More specifically, a heatabsorption mask plate (tungsten film) is formed on the under surface ofthe silicon plate 15 using a CVD method, etc. Then, the openings 16 athat penetrate the heat absorption mask plate are patterned. Then, theheat absorption mask 16 having the openings 16 a is formed by forming alarge opening in the silicon plate 15 in such a way that the openings 16a of the heat absorption mask plate are exposed. Then, the silicon plate15 provided with the heat absorption mask 16 obtained is pasted to theunder surface of the frame 20. At this time, alignment is performed insuch a way that the large opening of the frame 20 is aligned with thelarge opening of the silicon plate 15 to form the large opening 20 a.

[0129] Then, in the process shown in FIG. 5(b), the silicon plate 11provided with a large opening and the stencil mask plate 14′ areprepared. More specifically, the silicon plate 11 on the under surfaceof which an oxide film is formed is prepared first and a stencil maskplate 14′ (Si film) is formed on the oxide film using a CVD method, etc.

[0130] Then, the under surface of the heat absorption mask 16 on theupper surface of which the frame 20 and silicon plate 15 obtained in theprocess shown in FIG. 5(a) are provided is pasted to the upper surfaceof the silicon plate 11 on the under surface of which the stencil maskplate 14′ is provided.

[0131] Then, in the process shown in FIG. 5(c), the resist 17 which isphotosensitive to X-rays is applied to the under surface of the stencilmask plate 14′.

[0132] Then, in the process shown in FIG. 5(d), X-rays are irradiatedfrom the direction shown by an arrow in the drawing and the resist 17 issubject to a photoreaction in a self-aligning way through the heatabsorption mask 16. At this time, since X-rays pass through the stencilmask plate 14′, the resist 17 located below the opening 16 a is subjectto a photoreaction. Then, the resist is developed and the resistopenings 17 a are formed. Here, X-rays are irradiated, but it is alsopossible to apply a method for patterning the resist 17 by irradiatinglight such as KrF excimer laser, etc. However, when light such as KrFexcimer laser is irradiated, any material can be used to form the heatabsorption mask 16, but the heat absorption mask 16 needs to be formedwith a material that allows light of KrF excimer laser to penetrate. Ofcourse, it is necessary to use a material photosensitive to KrF excimerlaser, etc as the resist 17.

[0133] Then, in the process shown in FIG. 5(c), dry etching is appliedusing the resist 17 in which the resist openings 17 a are formed as themask to from the direction shown by an arrow in the drawing form thestencil mask 14 having the patterning openings 14 a formed in almost thesame pattern as the openings 16 a.

[0134] Through the process, the multi-layer structured exposure mask 1of this embodiment is obtained.

[0135] According to this method, the stencil mask 14 is formed based onthe heat absorption mask 16, and therefore there is no need to align theopenings 16 a of the heat absorption mask 16 with the patterningopenings 14 a of the stencil mask 14. Thus, the possibility that aposition difference will be generated between the openings 16 a andpatterning openings 14 a is reduced significantly compared to the method1. That is, this method provides the multi-layer structured exposuremask 1 in which the openings 16 a match the patterning openings 14 awith high accuracy.

[0136] This method uses either an anode junction or an adhesive as thetechnique for pasting the frame 20, silicon plate 15, heat absorptionmask 16, silicon plate 11 and stencil mask 14 to each other.

Method 3

[0137] First, in the process shown in FIG. 6(a), the frame 20 made ofglass and having a large opening, the silicon plate 15 having a largeopening almost as large as the large opening of the frame 20 and theheat absorption mask 16 having openings 16 a formed in almost the samepattern as the pattering openings 14 a provided for the stencil mask 14,which will be described later are prepared. More specifically, a heatabsorption mask plate (SiN film) is formed on the under surface of thesilicon plate 15 using a CVD method, etc. Then, the openings 16a thatpenetrate the heat absorption mask plate are patterned to form the heatabsorption mask 16. Then, a large opening is formed in the silicon plate15 in such a way that the openings 16 a of the heat absorption mask 16are exposed. Then, the silicon plate 15 provided with the heatabsorption mask 16 obtained is pasted to the under surface of the frame20. At this time, alignment is performed in such a way that the largeopening of the frame 20 is aligned with the large opening of the siliconplate 15 to form the large opening 20 a.

[0138] In the process shown in FIG. 6(b), the silicon plate 11 is pastedto the under surface of the heat absorption mask 16 on the upper surfaceof which the frame 20 and silicon plate 15 obtained in the process shownin FIG. 6(a) are provided. At this time, it is also possible to paste anSOI plate instead of the silicon plate 11.

[0139] Then, a stencil mask plate 14′ (glass) is formed on the siliconoxide film of the silicon plate 11 using a CVD method, etc.

[0140] Then, in the process shown in FIG. 6(c), dry etching is performedby using the heat absorption mask 16 as the mask from the directionshown by an arrow in the drawing to form the stencil mask 14 providedwith the patterning openings 14 a formed in almost the same pattern asthe openings 16 a.

[0141] Then, in the process shown in FIG. 6(d), wet etching is performedby using the frame 20 as the mask from the direction shown by an arrowin the drawing to selectively remove the silicon plate 11. At this time,the silicon plate 11 of the area in which the openings 16 a andpattering openings 14 a are formed is removed and the peripheral areawhere no opening 16 a or patterning opening 14 a is formed is allowed toremain. In this way, a hollow section is formed between the heatabsorption mask 16 and stencil mask 14.

[0142] In the processes, the multi-layer structured exposure mask 1 ofthis embodiment is obtained.

[0143] According to this method as in the case of the method 2, thestencil mask 14 is formed based on the heat absorption mask 16, andtherefore there is no need to align the openings 16 a of the heatabsorption mask 16 with the patterning openings 14 a of the stencil mask14. Thus, the possibility that a positional difference will be generatedbetween the openings 16 a and patterning openings 14 a is reducedsignificantly compared to the method 1. That is, this method providesthe multi-layer structured exposure mask 1 in which the openings 16 amatch the patterning openings 14 a with high accuracy.

[0144] This method uses either an anode junction or an adhesive as thetechnique for pasting the frame 20, silicon plate 15, heat absorptionmask 16, silicon plate 11 and stencil mask 14 to each other.

[0145] Furthermore, using a component made of a material with higheretching speed than the heat absorption mask 16 and the stencil maskplate 14′ instead of the silicon plate 11 makes it possible to easilyform the hollow section 11 a without causing almost any damage to thestencil mask 14 and heat absorption mask 16.

[0146] Or instead of the processes shown in FIG. 6(a) and FIG. 6(b), thefollowing processes can also be performed.

[0147] First, a heat absorption mask plate (SiN film), the silicon plate11 and the stencil mask plate 14′ (glass) are formed one by one on theunder surface of the silicon plate 15 by using a CVD method, etc. Then,the heat absorption mask 16 is formed by patterning the openings 16 athat penetrate the heat absorption mask plate after forming a largeopening in the silicon plate 15 in such a way as to expose the uppersurface of the heat absorption mask plate.

[0148] Then, the silicon plate 15 provided with the heat absorption mask16 obtained is pasted to the under surface of the frame 20 having alarge opening. At this time, alignment is performed in such a way thatthe large opening of the frame 20 is aligned with the large opening ofthe silicon plate 15 to form the large opening 20 a.

Modification Example

[0149] This embodiment has used a mask made up of a silicon (Si)substrate as the stencil mask 14, but the present invention is notlimited to this and it is also possible to use a mask formed of a filmselected from among glass, silicon nitride (SiN), silicon carbide (SiC),diamond, diamond-like, etc.

[0150] Furthermore, it is preferable that the heat absorption mask 16 bemade of a material having higher thermal conductivity than the stencilmask 14. This is because using such a material makes it possible toallow the heat absorption mask to absorb heat efficiently. Thisembodiment has used a mask made up of a silicon nitride (SiN) film asthe heat absorption mask 16, but the present invention is not limited tothis and it is also possible to use a mask formed of a film selectedfrom among silicon (Si) or silicon carbide (SiC), diamond, diamond-like,tungsten (W) and molybdenum.

[0151] By the way, the material of the stencil mask 14 is different fromthat of the heat absorption mask 16, but the same material can also beused. For example, it is also possible to use both masks formed ofsilicon substrates.

[0152] One heat absorption mask 16 is used in this embodiment, but it isalso possible to change the material of the mask, thickness and thenumber of masks according to the acceleration voltage of electron beams.For example, the heat absorption mask 16 can be formed of a siliconsubstrate coated with a diamond film with high thermal conductivity andonly one mask can be used. The mask can also be formed of a siliconsubstrate coated with a silicon nitride film with smaller thermalconductivity than diamond and three masks can be used.

[0153] This embodiment uses a frame made of glass as the frame 20, butthe frame can also be made of SiC and metal, etc.

[0154] It is also possible to provide a poly Si thin film (for example,poly silicon, SiO₂, BPSG (boron doped phosphorus silicate glass), etc.)instead of the silicon plates 11 and 15. Or a sapphire substrate canalso be used instead of the silicon plates 11 and 15.

Embodiment 2 Configuration of Multi-layer Structured Exposure Mask

[0155] This embodiment will be explained with reference to FIG. 7. FIG.7 is a cross-sectional view showing a configuration of a multi-layerstructured exposure mask according to this embodiment. The multi-layerstructured exposure mask is used for an X-ray exposure apparatus.

[0156] As shown in FIG. 7, the multi-layer structured exposure mask 1Aof this embodiment is provided with a frame 20 made of glass, a siliconplate 15 provided on the under surface of the frame 20, a heatabsorption mask 16 provided on the under surface of the silicon plate15, a silicon plate 11 provided on the under surface of the heatabsorption mask 16, a membrane 12 provided on the under surface of thesilicon plate 11 and an X-ray shielding metal film 13 provided on theunder surface of the membrane 12.

[0157] The membrane 12 is provided to support the X-ray shielding metalfilm 13 and formed of a material (SiC, diamond, etc.) that allows X-raysto penetrate.

[0158] The X-ray shielding metal film 13 is bonded with the membrane 12.In this embodiment, the X-ray shielding metal film 13 is formed oftungsten (W) and provided with a slit-shaped patterning opening 13 a toform a resist pattern.

[0159] The heat absorption mask 16 is formed of a silicon substratecoated with an SiN film and provided with openings 16 a formed in almostthe same pattern as the patterning openings 13 a of the X-ray shieldingmetal film 13. The openings 16 a are formed in such a size as to preventX-rays necessary to form resist patterns from being blocked. That is,the size of the openings 16 a is the same as the size of the patterningopenings 13 a or the size of the openings 16 a is a little larger.

[0160] Furthermore, the multi-layer structured exposure mask 1A of thisembodiment is provided with a large opening 20 a that penetrates theframe 20 and silicon plate 15 and exposes the area of the upper surfaceof the heat absorption mask 16 in which the openings 16 a are formed.

[0161] The multi-layer structured exposure mask 1A of this embodiment isfurther provided with a hollow section 11 a that penetrates the siliconplate 11 and exposes an area on the under surface of the heat absorptionmask 16 in which the openings 16 a are formed and the upper surface ofthe membrane 12 in the area in which the patterning openings 13 a of theX-ray shielding metal film 13 are formed.

[0162] In the multi-layer structured exposure mask 1A of thisembodiment, the patterning openings 13 a of the X-ray shielding metalfilm 13 and the openings 16 a of the heat absorption mask 16 are alignedin the horizontal direction as shown in FIG. 3(a).

[0163] The multi-layer structured exposure mask 1A of this embodiment isset with the frame 20 facing the X-ray source side of the X-ray exposureapparatus. Therefore, X-rays incident upon the large opening 20 a of themulti-layer structured exposure mask 1A pass through the openings 16 aand then pass through the membrane 12 and patterning openings 13 a.

[0164] As is apparent from the explanations, the multi-layer structuredexposure mask 1A of this embodiment has almost the same structure asthat of the multi-layer structured exposure mask 1 of Embodiment 1 andthe components thereof are the same as those of Embodiment 1. However,this embodiment is different from Embodiment 1 in that the membrane 12and X-ray shielding metal film 13 are provided instead of the stencilmask 14 of the multi-layer structured exposure mask 1 of Embodiment 1.

[0165] Unlike the conventional exposure mask, the multi-layer structuredexposure mask 1A of this embodiment is provided with the heat absorptionmask 16. The heat absorption mask 16 has a high heat absorption rate andremoves X-rays unnecessary to form a resist pattern out of X-raysirradiated onto the multi-layer structured exposure mask 1.

[0166] As in the case of Embodiment 1, the heat absorption mask 16 isprovided with the openings 16 a in such a size as to prevent X-raysnecessary to form a resist pattern from being blocked. That is, the sizeof the openings 16 a is equal to the size of the patterning opening 13 aof the X-ray shielding metal film 13 or the size of the openings 16 a ofthe heat absorption mask 16 is larger. The size of the openings 16 a ispreferably 150% of the size of the patterning openings 13 a or less.Furthermore, when the multi-layer structured exposure mask 1A of thisembodiment is used for applications where not so high accuracy in thelength direction of the patterning openings 13 a is required (forexample, formation of a wiring pattern), the openings 16 a can beshorter than the patterning openings 13 a.

[0167] In this embodiment, one heat absorption mask 16 formed of asilicon substrate which is coated with an SiN film is provided, the heatabsorption mask 16 has a thickness of 2 μm and the opening 16 a has awidth of 60 nm. The X-ray shielding metal film 13 has a thickness of 0.5μm and the patterning opening 13 a has a width of 50 nm. That is, theaspect ratio of the patterning opening 13 a is 10.

[0168] The opening 16 a of the heat absorption mask 16 is a littlelarger than the patterning opening 13 a of the X-ray shielding metalfilm 13 and the heat absorption mask 16 and X-ray shielding metal film13 are aligned in such a way as to prevent the heat absorption mask 16from blocking the patterning openings 13 a of the X-ray shielding metalfilm 13 when X-rays enter.

[0169] For this reason, most of X-rays that do not contribute toformation of the resist pattern out of X-rays irradiated onto themulti-layer structured exposure mask 1A of this embodiment are blockedby the heat absorption mask 16, which reduces X-rays irradiated onto theX-ray shielding metal film 13. Therefore, the heat absorption mask 16generates heat, while heat generation of the X-ray shielding metal film13 is suppressed. This suppresses or prevents deformation of the X-rayshielding metal film 13.

[0170] Furthermore, the heat absorption mask 16 is separated from themembrane 12 by the hollow section 11 a and the two do not contact eachother. Because of this, the heat generated in the heat absorption mask16 is mostly not transmitted to the X-ray shielding metal film 13 butdissipated to the outside through the silicon plate 15 and frame 20.This suppresses or prevents deformation of the X-ray shielding metalfilm 13.

[0171] As described above, the multi-layer structured exposure mask 1Aof this embodiment is provided with the heat absorption mask 16 toprotect the X-ray shielding metal film 13. Thus, using the multi-layerstructured exposure mask 1A of this embodiment suppresses or preventsdeformation of the X-ray shielding metal film 13 even when carrying outexposure to X-rays with high energy (e.g., SOR-X-rays (synchrotronorbital radiation X-ray)), making it possible to form a resist patternexactly matching the patterning openings 13 a.

[0172] The multi-layer structured exposure mask 1A of this embodimentalso displays an outstanding effect using plasma X-rays which have highenergy, discharge type X-rays, etc. in addition to SOR-X-rays.

[0173] Especially when SOR-X-rays are used, the SOR-X-ray beam emittedfrom the X-ray source has a rectangular shape. These SOR-X-rays arevibrated above and below the silicon wafer using mirrors to secure adrawing area. For this reason, the amount of X-rays irradiated onto theexposure mask is considerable. Thus, with the exposure mask onto whichrectangular X-ray beams are irradiated, there is concern about patterndisplacement due to a temperature rise. However, using the multi-layerstructured exposure mask 1A of this embodiment suppresses heatgeneration of the X-ray shielding metal film 13 and can thereby preventdeformation of the patterning openings 13 a.

Manufacturing Method

[0174] Then, the method for manufacturing the multi-layer structuredexposure mask 1A of this embodiment will be explained with reference toFIG. 8 and FIG. 9. Any of the following method 1A and method 2A can beused in this embodiment. FIG. 8 and FIG. 9 are process cross-sectionalviews showing the method for manufacturing the multi-layer structuredexposure mask 1A of this embodiment and correspond to the method 1A andmethod 2A shown below respectively.

Method 1A

[0175] First, in the process shown in FIG. 8(a), the frame 20 made ofglass and having a large opening, the silicon plate 15 having a largeopening almost as large as the large opening of the frame 20 and theheat absorption mask 16 having openings 16 a formed in almost the samepattern as the pattering openings 13 a provided for the X-ray shieldingmetal film 13, which will be described later are prepared. Morespecifically, a heat absorption mask plate (SiN film) is formed on theunder surface of the silicon plate 15 using a CVD method, etc. Then, theheat absorption mask 16 is formed by patterning the openings 16 a thatpenetrate the heat absorption mask plate. Then, a large opening isformed in the silicon plate 15 in such a way that the openings 16 a ofthe heat absorption mask 16 are exposed. Then, the silicon plate 15provided with the heat absorption mask 16 obtained is pasted to theunder surface of the frame 20. At this time, alignment is performed byaligning the large opening of the frame 20 with the large opening of thesilicon plate 15 to form the large opening 20 a.

[0176] Then, in the process shown in FIG. 8(b), the silicon plate 11provided with a large opening, the membrane 12 and the X-ray shieldingmetal film 13 provided with the patterning openings 13 a to form aresist pattern are prepared. More specifically, the membrane 12 andX-ray shielding metal plate are formed on the under surface of thesilicon plate 11 one by one using a CVD method, etc. Then, the X-rayshielding metal film 13 is formed by forming the patterning openings 13a that penetrate the X-ray shielding metal plate. Then, a large openingis formed in the silicon plate 11 in such a way that the upper surfaceof the membrane 12 in the area in which the patterning openings 13 a ofthe X-ray shielding metal film 13 are formed is exposed.

[0177] Then, in the process shown in FIG. 8(c), the under surface of theheat absorption mask 16 on the upper surface of which the frame 20 andsilicon plate 15 obtained in the process shown in FIG. 8(a) are providedis pasted to the upper surface of the silicon plate 11 on the undersurface of which the X-ray shielding metal film 13 is provided. At thistime, the openings 16 a of the heat absorption mask 16 and thepatterning openings 13 a of the X-ray shielding metal film 13 arealigned in the horizontal direction.

[0178] In the processes, the multi-layer structured exposure mask 1A ofthis embodiment is obtained.

[0179] This method uses either an anode junction or an adhesive as thetechnique for pasting the frame 20, silicon plate 15, heat absorptionmask 16, silicon plate 11, membrane 12 and X-ray shielding metal film 13to each other.

Method 2A

[0180] First, in the process shown in FIG. 9(a), the frame 20 made ofglass and having a large opening, the silicon plate 15 having a largeopening as large as the large opening of the frame 20 and the heatabsorption mask 16 having openings 16 a formed in almost the samepattern as the pattering openings 13 a provided for the X-ray shieldingmetal film 13, which will be described later, are prepared. Morespecifically, a heat absorption mask plate (SiN film) is formed on theunder surface of the silicon plate 15 using a CVD method, etc. Then, theheat absorption mask 16 is formed by patterning the openings 16 a thatpenetrate the heat absorption mask plate. Then, a large opening isformed in the silicon plate 15 so that the openings 16 a of the heatabsorption mask 16 are exposed. Then, the silicon plate 15 provided withthe heat absorption mask 16 obtained is pasted to the under surface ofthe frame 20. At this time, alignment is performed in such a way thatthe large opening of the frame 20 is aligned with the large opening ofthe silicon plate 15 to form the large opening 20 a.

[0181] Then, in the process shown in FIG. 9(b), the silicon plate 11provided with a large opening, the membrane 12 and the X-ray shieldingmetal plate 13′ are prepared. More specifically, the membrane 12 andX-ray shielding metal plate 13′ are formed on the under surface of thesilicon plate 11 one by one using a CVD method, etc. Then, a largeopening is formed in the silicon plate 11 so that the upper surface ofthe membrane 12 is exposed. Then, the under surface of the heatabsorption mask 16 obtained in the process shown in FIG. 9(a) on theupper surface of which the frame 20 and silicon plate 15 are provided ispasted to the upper surface of the silicon plate 11 on the under surfaceof which the X-ray shielding metal plate 13′ is provided.

[0182] Then, in the process shown in FIG. 9(c), the resist 17 which isphotosensitive to X-rays is applied to the under surface of the X-rayshielding metal plate 13′.

[0183] Then, in the process shown in FIG. 9(d), X-rays are irradiatedfrom the direction shown by an arrow in the drawing and the resist 17 issubject to a photoreaction in a self-aligning way through the heatabsorption mask 16. At this time, X-rays with intensity capable ofpenetrating the X-ray shielding metal plate 13′ are irradiated and theresist 17 located below the openings 16 a is subject to a photoreaction.X-rays used in this process have much higher intensity than X-rays usedin a normal X-ray exposure apparatus.

[0184] Then, the resist is developed to form resist openings 17 a.

[0185] Then, dry etching is applied using the resist 17 in which theresist opening 17 a is formed as the mask to form the X-ray shieldingmetal film 13 having patterning openings 13 a formed in almost the samepattern as the openings 16 a.

[0186] Then, by removing the resist 17, the multi-layer structuredexposure mask 1A of this embodiment is obtained.

[0187] According to this method, the X-ray shielding metal film 13 isformed based on the heat absorption mask 16, and therefore there is noneed to align the openings 16 a of the heat absorption mask 16 and thepatterning openings 13 a of X-ray shielding metal film 13. Thissignificantly reduces the possibility that there will be a positionaldifference between the openings 16 a and patterning openings 13 acompared to the method 1. That is, this method provides the multi-layerstructured exposure mask 1 in which the openings 16 a match thepatterning openings 13 a with high accuracy.

[0188] This method uses either an anode junction or an adhesive as thetechnique for pasting the frame 20, silicon plate 15, heat absorptionmask 16, silicon plate 11, membrane 12 and X-ray shielding metal film 13to each other.

Modification Example

[0189] This embodiment has used the X-ray shielding metal film 13 madeup of a tungsten (W) substrate, but the present invention is not limitedto this and it is also possible to use a X-ray shielding metal film madeof a material through which X-rays are hardly transmissible such asmolybdenum (Mo), vanadium (V) and tantalum (Ta).

[0190] Moreover, this embodiment uses only one heat absorption mask 16,but the material of the mask, thickness and the number of masks can bechanged according to a wavelength (energy) of X-rays. For example, theheat absorption mask 16 can be formed of a silicon substrate coated withdiamond with high thermal conductivity and one heat absorption mask canbe used. Or three heat absorption masks can be formed of a siliconsubstrate coated with a silicon nitride film which has smaller thermalconductivity than diamond.

[0191] Especially, the heat absorption mask 16 is preferably made of amaterial with higher thermal conductivity than that of the X-rayshielding metal film 13. This is because adopting such a material allowsthe heat absorption mask to absorb heat efficiently. This embodimentuses the heat absorption mask 16 formed of a silicon substrate coatedwith a silicon nitride (SiN) film, but the present invention is notlimited to this and it is also possible to use a heat absorption maskformed of a silicon substrate coated with a film selected from siliconcarbide (SiC), diamond, diamond-like, tungsten (W) and molybdenum (Mo).

[0192] By the way, this embodiment uses the X-ray shielding metal film13 and the heat absorption mask 16 made of different materials, but thesame material can also be used. For example, both can be formed of atungsten film.

[0193] Furthermore, this embodiment uses the frame 20 made of glass, butcan also use the frame 20 made of SiC and metal, etc.

[0194] Instead of the silicon plates 11 and 15, it is also possible toprovide a thin film such as poly silicon, SiO₂, BPSG (boron dopedphosphorus silicate glass), etc. Or it is possible to use a sapphireplate instead of the silicon plates 11 and 15.

Embodiment 3 Configuration of Multi-layer Structured Exposure Mask

[0195] This embodiment will be explained with reference to FIG. 10. FIG.10 is a cross-sectional view showing a configuration of a multi-layerstructured exposure mask according to this embodiment. The multi-layerstructured exposure mask in this embodiment is used for an electron beamexposure apparatus.

[0196] As shown in FIG. 10, the multi-layer structured exposure mask 1Bof this embodiment is provided with a frame 20 made of glass, a siliconplate 11 provided on the under surface of the frame 20, a stencil mask14 provided on the under surface of the silicon plate 11, a heatabsorption mask 16 provided on the upper surface of the frame 20 and asilicon plate 15 provided on the upper surface of the heat absorptionmask 16.

[0197] The stencil mask 14 is formed of a silicon substrate and providedwith slit-shaped patterning openings 14 a to form a resist pattern.

[0198] The heat absorption mask 16 is formed of a silicon substratecoated with an SiN film and provided with openings 16 a formed in almostthe same pattern as the patterning openings 14 a of the stencil mask 14.The openings 16 a are formed in such a size as to prevent electron beamsnecessary to form a resist pattern from being blocked. That is, the sizeof the opening 16 a is the same as the size of the patterning opening 14a or the size of the opening 16 a is a little larger.

[0199] Furthermore, the multi-layer structured exposure mask 1B of thisembodiment is provided with the hollow section 11 a, which penetratesthe frame 20 and silicon plate 11 and exposes an area of the undersurface of the heat absorption mask 16 in which the openings 16 a areformed and an area of the upper surface of the stencil mask 14 in whichthe patterning openings 14 a are formed.

[0200] In the multi-layer structured exposure mask 1B of thisembodiment, the patterning opening 14 a of the stencil mask 14 and theopening 16 a of the heat absorption mask 16 are aligned in thehorizontal direction as shown in FIG. 3(a).

[0201] The multi-layer structured exposure mask 1B of this embodiment isset with the frame 20 facing the electron gun 31 side of the EB exposureapparatus 100 as in the case of the multi-layer structured exposure mask1 of Embodiment 1 and electron beams are irradiated in the directionindicated by an arrow B in FIG. 10. At this time, electron beams thathave passed through the openings 16 a pass through the patterningopenings 13 a.

[0202] As is apparent from the explanations, the multi-layer structuredexposure mask 1B of this embodiment has almost the same structure asthat of the multi-layer structured exposure mask 1 of Embodiment 1 andthe components thereof are the same as those of Embodiment 1. However,this embodiment is different from the multi-layer structured exposuremask 1 of Embodiment 1 only in the pasting order of the frame 20 andsilicon plate 15 (heat absorption mask 16).

[0203] As in the case of the multi-layer structured exposure mask 1 ofEmbodiment 1, the multi-layer structured exposure mask 1B of thisembodiment is provided with the heat absorption mask 16. This suppressesdeformation of the stencil mask 14 due to thermal expansion just likethe multi-layer structured exposure mask 1 of Embodiment 1, allowingmore accurate formation of the resist pattern.

[0204] Furthermore, the heat absorption mask 16 and stencil mask 14 areseparated by the hollow section 11 a and do not directly touch eachother. For this reason, almost no heat generated in the heat absorptionmask 16 is transmitted to the stencil mask 14 but dissipated to theoutside through the silicon plate 15 and frame 20. This suppresses orprevents deformation of the stencil mask 14.

[0205] It is also possible to apply the modification example describedin Embodiment 1 to the multi-layer structured exposure mask 1B of thisembodiment and the effect obtained by that modification can also beobtained likewise.

Manufacturing Method

[0206] Then, the method for manufacturing the multi-layer structuredexposure mask 1B of this embodiment will be explained with reference toFIG. 11. FIG. 11 is a process cross-sectional view showing the methodfor manufacturing the multi-layer structured exposure mask 1 accordingto this embodiment.

[0207] First, in the process shown in FIG. 11(a), the silicon plate 15having a large opening 15 a, the heat absorption mask 16 having openings16 a formed in almost the same pattern as the pattering openings 14 aprovided for the stencil mask 14, which will be described later, areprepared. More specifically, a heat absorption mask plate (SiN film) isformed on the under surface of the silicon plate 15 using a CVD method,etc. Then, the heat absorption mask 16 is formed by patterning theopenings 16 a that penetrate the heat absorption mask plate. Then, alarge opening is formed in the silicon plate 15 in such a way that theopenings 16 a of the heat absorption mask 16 are exposed.

[0208] Then, in the process shown in FIG. 11(b), the frame 20 made ofglass and having a large opening, the silicon plate 11 provided with alarge opening almost as large as the large opening of the frame 20 andthe stencil mask plate 14′ are prepared. More specifically, the siliconplate 11 with a silicon oxide film formed on the under surface isprepared first and a stencil mask plate 14′ (Si film) is formed on thesilicon oxide film using a CVD method, etc. Then, a large opening isformed in the silicon plate 11 in such a way that the upper surface ofthe stencil mask plate 14′ is exposed. Then, the silicon plate 11 ispasted to the under surface of the frame 20. At this time, alignment isperformed in such a way that the large opening of the frame 20 isaligned with the large opening of the silicon plate 11.

[0209] Then, in the process shown in FIG. 11(c), a resist 17 is formedon the upper surface of the stencil mask plate 14′ exposed in the largeopening of the silicon plate 11.

[0210] Then, the under surface of the heat absorption mask 16 on theupper surface of which the silicon plate 15 is provided is pasted to theupper surface of the silicon plate 11 the under surface of which theframe 20 and stencil mask plate 14′ are provided. At this time,alignment is performed in such a way that the large opening of the frame20 faces the area of the under surface of the heat absorption mask 16 inwhich the openings 16 a are formed.

[0211] By the way, after pasting the under surface of the heatabsorption mask 16 on the upper surface of which the silicon plate 15 isprovided to the upper surface of the silicon plate 11 on the undersurface of which the frame 20 and stencil mask plate 14′ are provided inthis process, it is also possible to form the resist 17 on the uppersurface of the stencil mask plate 14′.

[0212] Then, in the process shown in FIG. 11(d), X-rays are irradiatedfrom the direction shown by an arrow in the drawing and the resist 17 issubject to a photoreaction in a self-aligning way through the heatabsorption mask 16. Then, the resist is developed to form resistopenings 17 a.

[0213] Then, dry etching is applied using the resist 17 in which theresist openings 17 a are formed as the mask from the direction indicatedby the arrow in the drawing to form a stencil mask 14 having patterningopenings 14 a formed in almost the same pattern as the openings 16 a.

[0214] In the processes, the multi-layer structured exposure mask 1 ofthis embodiment is obtained.

[0215] According to this method, the stencil mask 14 is formed based onthe heat absorption mask 16, and therefore there is no need to align theopenings 16 a of the heat absorption mask 16 and the patterning openings14 a of the stencil mask 14. This significantly reduces the possibilitythat there will be a positional difference between the openings 16 a andpatterning openings 14 a. That is, this method provides the multi-layerstructured exposure mask 1B in which the opening 16 a matches thepatterning opening 14 a with high accuracy.

[0216] This method uses either an anode junction or an adhesive as thetechnique for pasting the frame 20, silicon plate 15, heat absorptionmask 16, silicon plate 11 and stencil mask 14 to each other.

[0217] Furthermore, the multi-layer structured exposure mask 1B of thisembodiment is different from the multi-layer structured exposure mask 1of Embodiment 1 only in the pasting order of the frame 20, silicon plate15 and heat absorption mask 16. Therefore, in the method 1 described inEmbodiment 1, by changing the pasting order of the frame 20, siliconplate 15 and heat absorption mask 16, it is possible to prepare themulti-layer structured exposure mask 1B of this embodiment.

Embodiment 4 Configuration of Multi-layer Structured Exposure Mask

[0218] This embodiment will be explained with reference to FIG. 12. FIG.12 is a cross-sectional view showing a configuration of a multi-layerstructured exposure mask according to this embodiment. The multi-layerstructured exposure mask is used for an X-ray exposure apparatus.

[0219] As shown in FIG. 12, the multi-layer structured exposure mask 1Cof this embodiment is provided with a frame 20 made of glass, a siliconplate 11 provided on the under surface of the frame 20, a membrane 12provided on the under surface of the silicon plate 11, an X-rayshielding metal film 13 provided on the under surface of the membrane12, a heat absorption mask 16 provided on the upper surface of the frame20 and a silicon plate 15 provided on the upper surface of the heatabsorption mask 16.

[0220] The membrane 12 is provided to hold the X-ray shielding metalfilm 13 and formed of a material allowing X-rays to penetrate (SiC,diamond, etc.).

[0221] The X-ray shielding metal film 13 is bonded with the membrane 12.In this embodiment, the X-ray shielding metal film 13 is formed oftungsten and provided with a slit-shaped patterning opening 13 a to forma resist pattern.

[0222] The heat absorption mask 16 is formed of a silicon substratecoated with an SiN film and provided with openings 16 a formed in almostthe same pattern as the patterning openings 13 a of the X-ray shieldingmetal film 13. The openings 16 a are formed in such a size as to preventX-rays necessary to form resist patterns from being blocked. That is,the size of the opening 16 a is the same as the size of the patterningopening 13 a or the size of the opening 16 a is a little larger.

[0223] Furthermore, the multi-layer structured exposure mask 1C of thisembodiment is provided with a hollow section 11 a, which penetrates theframe 20 and silicon plate 11 and exposes an area of the heat absorptionmask 16 in which the openings 16 a are formed and the upper surface ofthe membrane 12 of the area in which the patterning openings 13 a of theX-ray shielding metal film 13 are formed.

[0224] In the multi-layer structured exposure mask 1C of thisembodiment, the patterning openings 13 a of the X-ray shielding metalfilm 13 and the openings 16 a of the heat absorption mask 16 are alignedin the horizontal direction as shown in FIG. 3(a).

[0225] The multi-layer structured exposure mask 1C of this embodiment isset with the silicon plate 15 facing the X-ray source side of the X-rayexposure apparatus. Therefore, X-rays that have passed through theopenings 16 a pass through the membrane 12 and then pass through thepatterning openings 13 a.

[0226] As is apparent from the explanations, the multi-layer structuredexposure mask 1C of this embodiment has almost the same structure asthat of the multi-layer structured exposure mask 1B of Embodiment 3 andthe components thereof are almost the same as those of Embodiment 1.However, this embodiment is different only in that the membrane 12 andX-ray shielding metal film 13 are provided instead of the stencil mask14 of the multi-layer structured exposure mask 1B of Embodiment 3.

[0227] As in the case of the multi-layer structured exposure mask 1A ofEmbodiment 2, the multi-layer structured exposure mask 1C of thisembodiment is provided with the heat absorption mask 16. This suppressesdeformation of the X-ray shielding metal film 13 due to thermalexpansion just like the multi-layer structured exposure mask 1A ofEmbodiment 1, allowing more accurate formation of resist patterns.

[0228] Furthermore, the heat absorption mask 16 and X-ray shieldingmetal film 13 are separated by the hollow section 11 a and do notdirectly touch each other. For this reason, almost no heat generated inthe heat absorption mask 16 is transmitted to the X-ray shielding metalfilm 13 but dissipated to the outside through the silicon plate 15 andframe 20. This suppresses or prevents deformation of the X-ray shieldingmetal film 13.

[0229] It is also possible to apply the modification example describedin Embodiment 2 to the multi-layer structured exposure mask 1C of thisembodiment and the effect obtained by that modification can also beobtained likewise.

Manufacturing Method

[0230] Then the method for manufacturing the multi-layer structuredexposure mask 1A of this embodiment will be explained with reference toFIG. 13 and FIG. 14. Either of the following method 1A or method 2A canbe used in this embodiment. FIG. 13 and FIG. 14 are processcross-sectional views showing the method for manufacturing themulti-layer structured exposure mask 1C according to this embodiment andcorrespond to the method 1C and method 2C respectively.

Method 1C

[0231] First, in the process shown in FIG. 13(a), the silicon plate 15having a large opening 15 a, the heat absorption mask 16 having openings16 a formed in almost the same pattern as the pattering openings 13 aprovided for the X-ray shielding metal film 13, which will be describedlater, are prepared. More specifically, a heat absorption mask plate(SiN film) is formed on the under surface of the silicon plate 15 usinga CVD method, etc. Then, the heat absorption mask 16 is formed bypatterning the openings 16 a that penetrate the heat absorption maskplate. Then, a large opening 15 a is formed in the silicon plate 15 insuch a way that the openings 16 a of the heat absorption mask 16 areexposed.

[0232] Then, in the process shown in FIG. 13(b), the silicon plate 11having a large opening, membrane 12 and X-ray shielding metal film 13provided with the patterning openings 13 a to form a resist pattern areprepared. More specifically, the membrane 12 and X-ray shielding metalplate are formed on the under surface of the silicon plate 11 one by oneusing a CVD method, etc. Then, the X-ray shielding metal film 13 isformed by forming the patterning openings 13 a that penetrate the X-rayshielding metal plate. Then, a large opening is formed in the siliconplate 11 in such a way as to expose the upper surface of the membrane 12of the area in which the patterning openings 13 a of the X-ray shieldingmetal film 13 are formed.

[0233] Then, in the process shown in FIG. 13(c), the frame 20 made ofglass and having a large opening is prepared. Then, the upper surface ofthe frame 20 is passed to the under surface of the heat absorption mask16 on the upper surface of which the silicon plate 15 is provided andwhich is obtained in the process shown in FIG. 3(a). Then, the undersurface of the frame 20 is pasted to the upper surface of the siliconplate 11 on the under surface of which the X-ray shielding metal film 13obtained in the process shown in FIG. 13(b) is provided. At this time,the openings 16 a of the heat absorption mask 16 and the patterningopenings 13 a of the X-ray shielding metal film 13 are aligned in thehorizontal direction.

[0234] In the processes, the multi-layer structured exposure mask 1C ofthis embodiment is obtained.

[0235] This method uses either an anode junction or an adhesive as thetechnique for pasting the frame 20, silicon plate 15, heat absorptionmask 16, silicon plate 11, membrane 12 and X-ray shielding metal film 13to each other.

Method 2C

[0236] First, in the process shown in FIG. 14(a), the silicon plate 15having a large opening 15 a and the heat absorption mask 16 providedwith openings 16 a formed in almost the same pattern as the patteringopenings 13 a provided for the X-ray shielding metal film 13, which willbe described later, are prepared. More specifically, a heat absorptionmask plate (SiN film) is formed on the under surface of the siliconplate 15 using a CVD method, etc. Then, the heat absorption mask 16 isformed by patterning the openings 16 a that penetrate the heatabsorption mask plate. Then, a large opening 15 a is formed in thesilicon plate 15 in such a way that the openings 16 a of the heatabsorption mask 16 are exposed.

[0237] In the process shown in FIG. 14(b), the membrane 12 and X-rayshielding metal plate 13′ are formed one by one on the under surface ofthe silicon plate 11 using a CVD method, etc. Then, a large opening isformed in the silicon plate 11 in such a way that the upper surface ofthe membrane 12 is exposed. Then, a resist 17 is formed on the undersurface of the X-ray shielding metal plate 13′.

[0238] Then, in the process shown in FIG. 14(c), the frame 20 made ofglass and having a large opening is prepared. Then, the upper surface ofthe frame 20 is pasted to the under surface of the heat absorption mask16 on the upper surface of which the silicon plate 15 obtained in theprocess shown in FIG. 14(a) is provided. Then, the under surface of theframe 20 is pasted to the upper surface of the silicon plate 11 on theunder surface of which the membrane 12, X-ray shielding metal plate 13′and the resist 17 obtained in the process shown in FIG. 14(b) areprovided.

[0239] Then, in the process shown in FIG. 14(d), X-rays are irradiatedfrom the direction shown by an arrow in the drawing and the resist 17 issubject to a photoreaction in a self-aligning way through the heatabsorption mask 16. At this time, X-rays with intensity capable ofpenetrating the X-ray shielding metal plate 13′ are irradiated and theresist 17 located below the openings 16 a is subject to a photoreaction.X-rays used in this process have much higher intensity than X-rays usedin a normal X-ray exposure apparatus.

[0240] Then, the resist is developed to form resist openings 17 a.

[0241] Then, in the process shown in FIG. 14(e) dry etching is appliedusing the resist 17 in which the resist openings 17 a are formed as themask to form the X-ray shielding metal film 13 having patterningopenings 13 a formed in almost the same pattern as the openings 16 a.Then, by removing the resist 17, the multi-layer structured exposuremask 1C of this embodiment is obtained.

[0242] According to this method, the X-ray shielding metal film 13 isformed based on the heat absorption mask 16, and therefore there is nodeed to align the openings 16 a of the heat absorption mask 16 and thepatterning openings 13 a of the X-ray shielding metal film 13. Thissignificantly reduces the possibility that there will be a positionaldifference between the openings 16 a and the patterning openings 13 acompared to the method 1C. That is, this method provides the multi-layerstructured exposure mask 1C with the openings 16 a and the patterningopenings 13 a aligned with high accuracy.

[0243] This method uses either an anode junction or an adhesive as thetechnique for pasting the frame 20, silicon plate 15, heat absorptionmask 16, silicon plate 11, membrane 12 and X-ray shielding metal film 13to each other.

Embodiment 5 Configuration of Multi-layer Structured Exposure Mask

[0244] This embodiment will be explained with reference to FIG. 15 andFIG. 16. FIG. 15 is a cross-sectional view showing a configuration of amulti-layer structured exposure mask according to this embodiment. FIG.16 is a top view of the multi-layer structured exposure mask accordingto this embodiment and a cross-sectional view along a line X-X in thedrawing corresponds to FIG. 15. The multi-layer structured exposure maskof this embodiment is used for an electron beam exposure apparatus.

[0245] As shown in FIG. 15, the multi-layer structured exposure mask 1Dof this embodiment is provided with a frame 21 made of glass, a siliconplate 11 provided on the under surface of the frame 21, a stencil mask14 provided on the under surface of the silicon plate 11, a heatabsorption mask 16 provided on the upper surface of the frame 21 and asilicon plate 15 provided on the upper surface of the heat absorptionmask 16.

[0246] The stencil mask 14 is formed of a silicon substrate and providedwith slit-shaped patterning openings 14 a to form a resist pattern.

[0247] The heat absorption mask 16 is formed of a silicon substratecoated with an SiN film and provided with openings 16 a formed in almostthe same pattern as the patterning openings 14 a of the stencil mask 14.The opening 16 a is formed in such a size as to prevent electron beamsnecessary to form resist patterns from being blocked. That is, the sizeof the opening 16 a is the same as the size of the patterning opening 14a or the size of the opening 16 a is a little larger.

[0248] The frame 21 has a concave section 21 a. The size of the concavesection 21 a is almost the same as that of the silicon plate 15 and theheat absorption mask 16. The silicon plate 15 and heat absorption mask16 are fitted in the concave section 21 a.

[0249] Furthermore, the multi-layer structured exposure mask 1B of thisembodiment is provided with a hollow section 21 b that penetrates theframe 21 and the silicon plate 11 and exposes an area of the undersurface of the heat absorption mask 16 in which the openings 16 a areformed and an area of the upper surface of the stencil mask 14 in whichthe patterning openings 14 a are formed.

[0250] In the multi-layer structured exposure mask 1D of thisembodiment, the patterning openings 14 a of the stencil mask 14 and theopenings 16 a of the heat absorption mask 16 are aligned in thehorizontal direction as shown in FIG. 16.

[0251] The multi-layer structured exposure mask 1D of this embodiment isset with the frame 21 facing the electron beam 31 side of the EBexposure apparatus 100 as in the case of the multi-layer structuredexposure mask 1 of Embodiment 1. At this time, electron beams that havepassed through the openings 16 a pass through the patterning openings 14a.

[0252] As is apparent from the explanations, the multi-layer structuredexposure mask 1D of this embodiment has almost the same structure asthat of the multi-layer structured exposure mask 1B of Embodiment 3 andthe components are the same as those of Embodiment 1. However, thisembodiment is different from the multi-layer structured exposure mask 1Bof Embodiment 3 in that the silicon plate 15 and heat absorption mask 16are fitted in the concave section 21 a of the frame 21.

[0253] As in the case of the multi-layer structured exposure mask 1B ofEmbodiment 1, the multi-layer structured exposure mask 1D of thisembodiment is provided with the heat absorption mask 16. This suppressesdeformation of the stencil mask 14 due to thermal expansion just likethe multi-layer structured exposure mask 1 of Embodiment 1, allowingmore accurate formation of resist patterns.

[0254] Furthermore, the heat absorption mask 16 and stencil mask 14 areseparated by the hollow section 11 a and do not directly touch eachother. For this reason, almost no heat generated in the heat absorptionmask 16 is transmitted to the stencil mask 14 but dissipated to theoutside through the silicon plate 15 and frame 20. This suppresses orprevents deformation of the stencil mask 14.

[0255] Especially, the size of the concave section 21 a is almost thesame as that of the silicon plate 15 and the heat absorption mask 16 andthe silicon plate 15 and the heat absorption mask 16 are fitted in theconcave section 21 a. For this reason, the silicon plate 15 and the heatabsorption mask 16 are securely fixed. This allows accurate alignmentbetween the patterning openings 14 a and the openings 16 a.

[0256] By the way, the modification example described in Embodiment 1 isalso applicable to the multi-layer structured exposure mask 1D of thisembodiment and the same effect can also be obtained by the modificationthereof.

Manufacturing Method

[0257] Then, the method for manufacturing the multi-layer structuredexposure mask 1D of this embodiment will be explained with reference toFIG. 17. FIG. 17 is a process cross-sectional view showing the methodfor manufacturing the multi-layer structured exposure mask 1D accordingto this embodiment.

[0258] First, in the process shown in FIG. 17(a), the silicon plate 15having a large opening 15 a, the heat absorption mask 16 having openings16 a formed in almost the same pattern as the pattering openings 14 aprovided for the stencil mask 14, which will be described later, areprepared. More specifically, a heat absorption mask plate (SiN film) isformed on the under surface of the silicon plate 15 using a CVD method,etc. Then, the heat absorption mask 16 is formed by patterning theopenings 16 a that penetrate the heat absorption mask plate. Then, alarge opening 15 a is formed in the silicon plate 15 in such a way thatthe openings 16 a of the heat absorption mask 16 are exposed.

[0259] Then, the frame 21 made of glass having a concave section 21 aand a large opening in the concave section 21 a is prepared, the heatabsorption mask 16 on the upper surface of which the silicon plate 15 isprovided is fitted in the concave section 21 a. At this time, the undersurface of the heat absorption mask 16 is pasted to the bottom face ofthe concave section 21 a of the frame 21.

[0260] Then, in the process shown in FIG. 17(b), the silicon plate 11provided with a large opening almost as large as the large opening ofthe frame 21 and the stencil mask plate 14′ are prepared. Morespecifically, a silicon plate 11 on the under surface of which a siliconoxide film is formed is prepared and a stencil mask plate 14′ (Si film)is formed on the silicon oxide film using a CVD method, etc. Then, alarge opening is formed in the silicon plate 11 in such a way that theupper surface of the stencil mask plate 14′ is exposed. Then, thesilicon plate 11 is pasted to the under surface of the frame 20. At thistime, alignment is performed in such a way that the large opening of theframe 20 is aligned with the large opening of the silicon plate 11.

[0261] In this process, it is also possible to form the resist 17 on theupper surface of the stencil mask plate 14′ after pasting the siliconplate 11 on the under surface of the frame 20.

[0262] Then, in the process shown in FIG. 17(c), X-rays are irradiatedfrom the direction shown by an arrow in the drawing and the resist 17 issubject to a photoreaction in a self-aligning way through the heatabsorption mask 16. Then, the resist is developed to form resistopenings 17 a.

[0263] Then, in the process shown in FIG. 17(d), dry etching is appliedusing the resist 17 in which the resist openings 17 a are formed as themask to form a stencil mask 14 having patterning openings 14 a formed inalmost the same pattern as the openings 16 a.

[0264] In the processes, the multi-layer structured exposure mask 1D ofthis embodiment is obtained.

[0265] According to this method, the stencil mask 14 is formed based onthe heat absorption mask 16, and therefore there is no need to align theopenings 16 a of the heat absorption mask 16 and the patterning openings14 a of the stencil mask 14. Particularly since the heat absorption mask16 is fitted in the concave section 21 a and fixed, there is almost nopossibility that there will be a positional difference between theopenings 16 a and patterning openings 14 a. That is, this methodprovides the multi-layer structured exposure mask 1D in which theopenings 16 a match the patterning openings 14 a with high accuracy.

[0266] This method uses either an anode junction or an adhesive as thetechnique for pasting the frame 21, silicon plate 15, heat absorptionmask 16, silicon plate 11, and stencil mask 14 to each other.

[0267] Furthermore, as another method for manufacturing the multi-layerstructured exposure mask 1D of this embodiment, it is also possible touse a method for pasting the silicon plate 11 to the under surface ofthe frame 21 and pasting the stencil mask 14 while aligning the openings16 a and patterning openings 14 a after the process shown in FIG. 7(a).

[0268] As described above, this embodiment has described the exposuremask for an electron beam exposure apparatus, but it is also possible toprovide the exposure mask for an X-ray exposure apparatus by providing alaminated film with an X-ray shielding metal film provided with amembrane and patterning openings instead of the stencil mask 14.

Embodiment 6

[0269] This embodiment will be explained with reference to FIG. 18. FIG.18 is a cross-sectional view showing a configuration of a multi-layerstructured exposure mask according to this embodiment. The multi-layerstructured exposure mask 1E of this embodiment is used for an electronbeam exposure apparatus.

[0270] As shown in FIG. 18, the multi-layer structured exposure mask 1Eof this embodiment is provided with a frame 21 provided with a concavesection 21 a, a stencil masks 14, a silicon plate 11, a heat absorptionmasks 16 and a silicon plates 15 provided in that order from the bottomface side within the concave section 21 a. Especially, this embodimentprovides three heat absorption masks 16 forming one body with thesilicon plates 15, but a heat absorption effect can be achieved onlywith at least one heat absorption mask 16.

[0271] The stencil mask 14 is formed of a silicon substrate and providedwith slit-shaped patterning openings 14 a to form a resist pattern.

[0272] The heat absorption mask 16 is formed of a silicon substratecoated with an SiN film and provided with openings 16 a formed in almostthe same pattern as the patterning openings 14 a of the stencil mask 14.The openings 16 a are formed in such a size as to prevent electron beamsnecessary to form resist patterns from being blocked. That is, the sizeof the opening 16 a is the same as the size of the patterning opening 14a or the size of the opening 16 a is a little larger.

[0273] Both the silicon plates 11 and 15 have a large opening. The largeopening of the silicon plate 11 is provided in the area of the uppersurface of the stencil mask 14 in which the patterning openings 14 a areformed. On the other hand, the large opening of the silicon plate 15 isprovided in the area of the upper surface of the heat absorption mask 16in which the openings 16 a are formed. The silicon plates 11 and 15provide space between the stencil mask 14 and the heat absorption mask16 and between the two heat absorption masks 16.

[0274] The size of the concave section 21 a of the frame 21 is almostthe same as that of the stencil mask 14, the silicon plate 11, the heatabsorption mask 16 and the silicon plate 15. Furthermore, a largeopening 21 c is provided inside the concave section 21 a and the largeopening 21 c exposes the area of the under surface of the stencil mask14 in which the patterning openings 14 a are formed.

[0275] In the multi-layer structured exposure mask 1E of thisembodiment, the patterning openings 14 a of the stencil mask 14 and theopenings 16 a of the heat absorption mask 16 are aligned in thehorizontal direction.

[0276] The multi-layer structured exposure mask 1E of this embodiment isset with the frame 21 facing the electron gun 31 side of the EB exposureapparatus 100 as in the case of the multi-layer structured exposure mask1 of Embodiment 1. At this time, electron beams that have passed throughthe openings 16 a pass through the patterning openings 14 a.

[0277] As is apparent from the explanations, the multi-layer structuredexposure mask 1E of this embodiment has almost the same structure asthat of the multi-layer structured exposure mask 1D of Embodiment 5 andthe components are the same as those of Embodiment 1. However, thisembodiment is different from the multi-layer structured exposure mask 1Dof Embodiment 5 in that the silicon plate 11, stencil mask 14, aplurality of silicon plates 15 and heat absorption masks 16 are fittedin the concave section 21 a of the frame 21.

[0278] As in the case of the multi-layer structured exposure mask 1D ofEmbodiment 5, the multi-layer structured exposure mask 1E of thisembodiment is provided with the heat absorption mask 16. This suppressesdeformation of the stencil mask 14 due to thermal expansion just likethe multi-layer structured exposure mask 1D of Embodiment 5, allowingmore accurate formation of resist patterns. Especially since thisembodiment provides a plurality of heat absorption masks 16, theefficiency of heat absorption is enhanced. For this reason, deformationof the stencil mask 14 due to thermal expansion is further suppressed.

[0279] Furthermore, the heat absorption mask 16 and stencil mask 14 areseparated by the hollow section 11 a and do not directly touch eachother. For this reason, almost no heat generated in the heat absorptionmask 16 is transmitted to the stencil mask 14 but dissipated to theoutside through the silicon plate 15 and frame 20. This suppresses orprevents deformation of the stencil mask 14.

[0280] Furthermore, the size of the concave section 21 a in thisembodiment is almost the same as that of the silicon plate 11, stencilmask 14, silicon plate 15 and the heat absorption mask 16 and thesilicon plate 15 and the heat absorption mask 16 are fitted in theconcave section 21 a. For this reason, the silicon plate 15 and the heatabsorption mask 16 are securely fixed. This allows accurate alignmentbetween the patterning opening 14 a and the opening 16 a.

[0281] By the way, the modification example described in Embodiment 1 isalso applicable to the multi-layer structured exposure mask 1E of thisembodiment and the same effect can also be obtained by the modificationthereof.

Manufacturing Method

[0282] Then, the method for manufacturing the multi-layer structuredexposure mask 1E of this embodiment will be explained with reference toFIG. 19. FIG. 19 is a process cross-sectional view showing the methodfor manufacturing the multi-layer structured exposure mask 1E accordingto this embodiment.

[0283] First, in the process shown in FIG. 19(a), the silicon plate 11having a large opening and a stencil mask 14 having patterning openings14 a are prepared. More specifically, the silicon plate 11 with asilicon oxide film formed on the under surface is prepared and a stencilmask plate (Si film) is formed on the silicon oxide film using a CVDmethod, etc. Then, the stencil mask 14 is formed by forming thepatterning openings 14 a that penetrate the stencil mask plate. Then, alarge opening is formed in the silicon plate 11 in such a way that thepatterning openings 14 a of the stencil mask 14 are exposed.

[0284] Then, a frame 21 made of glass and provided with a concavesection 21 a almost as large as the stencil mask 14 and furtherincluding a large opening 21 c inside the concave section 21 a isprepared. Then, the stencil mask 14 on the upper surface of which thesilicon plate 11 is provided is fitted in the concave section 21 a. Atthis time, the under surface of the stencil mask 14 is pasted to thebottom face of the concave section 21 a.

[0285] Then, in the process shown in FIG. 19(b), a silicon plate 15provided with a large opening almost as large as the large opening 21 cof the frame 21 and a heat absorption mask plate 16′ are prepared. Morespecifically, a heat absorption mask plate 16′ is formed on the undersurface of the silicon plate 15 using a CVD method, etc. first. Then, alarge opening is formed in the silicon plate 15 in such a way that theupper surface of the heat absorption mask plate 16′ is exposed. Then, aresist 17 is formed on the upper surface of the heat absorption maskplate 16′ exposed within the large opening of the silicon plate 15.

[0286] Then, the silicon plate 15 is pasted to the under surface of theframe 21. At this time, alignment is performed in such a way that thelarge opening 21 c of the frame 21 matches the large opening of thesilicon plate 15. Then, X-rays are irradiated through the stencil mask14 and the resist 17 is subject to a photoreaction in a self-aligningway. Then, the resist 17 is developed to form resist openings 17 a.

[0287] In this process, it is also possible to form the resist 17 on theupper surface of the heat absorption mask plate 16′ after pasting theunder surface of the frame 21 to the upper surface of the silicon plate15.

[0288] This embodiment repeats the process shown in FIG. 19(b) threetimes.

[0289] Then, in the process shown in FIG. 19(c), the heat absorptionmask plates 16′ provided with the three patterned resists 17 obtained inthe process shown in FIG. 19(b) are fitted in the concave section 21 aof the frame 21.

[0290] Then, in the process shown in FIG. 19(d), dry etching is appliedusing the resist 17 in which the resist openings 17 a are formed as themask to form three heat absorption masks 16 having patterning openings16 a formed in almost the same pattern as the patterning openings 14 a.

[0291] In the processes, the multi-layer structured exposure mask 1E ofthis embodiment is obtained.

[0292] According to this method, the heat absorption mask 16 is formedbased on the stencil mask 14, and therefore there is no need to alignthe openings 16 a of the heat absorption mask 16 with the patterningopenings 14 a of the stencil mask 14. Furthermore, the stencil mask 14and the heat absorption mask 16 are fitted in the concave section 21 aand fixed according to this embodiment, and therefore there is littlepossibility that there will be a positional difference between theopenings 16 a and patterning openings 14 a. That is, this methodprovides the multi-layer structured exposure mask 1E in which theopenings 16 a match the patterning openings 14 a with high accuracy.

[0293] Furthermore, it is also possible to apply dry etching using theresist 17 in which the resist openings 17 a are formed as the mask toform the heat absorption mask 16 in the process shown in FIG. 19(b), andfit the heat absorption mask 16 obtained in the process shown in FIG.19(b) in the concave section 21 a of the frame 21 in the process shownin FIG. 19(c) and remove the resist 17 in the process shown in FIG.19(d).

[0294] This method uses either an anode junction or an adhesive as atechnique for pasting the frame 21, silicon plate 15, heat absorptionmask 16, silicon plate 11 and stencil mask 14 to each other.

Modification Example

[0295] As shown above, this embodiment has described the exposure maskfor an electron beam exposure apparatus, but it is also possible toprovide the exposure mask for an X-ray exposure apparatus by providing alaminated film with an X-ray shielding metal film provided with amembrane and patterning openings instead of the stencil mask 14.

[0296] Moreover, this embodiment has a configuration with three heatabsorption masks 16, but at least one heat absorption mask 16 candisplay a heat absorption effect.

Embodiment 7

[0297] This embodiment will be explained with reference to FIG. 20. FIG.20 is a cross-sectional view showing a configuration of a multi-layerstructured exposure mask according to this embodiment. FIG. 21 is a topview of the multi-layer structured exposure mask 1 of this embodimentand the sectional view along the Y-Y line in the drawing corresponds toFIG. 20. The multi-layer structured exposure mask IF of this embodimentis used for an electron beam exposure apparatus.

[0298] As shown in FIG. 20, the multi-layer structured exposure mask 1Fof this embodiment is provided with a frame 21 with a concave section 21a, a stencil mask 14, a silicon plate 11, heat absorption masks 16 andsilicon plates 15 and a metal cover 22 provided in that order from thebottom face side inside the concave section 21 a. Especially, thisembodiment provides three heat absorption masks 16 forming one body withthe silicon plates 15, but a heat absorption effect can be achieved onlywith at least one heat absorption mask 16.

[0299] The stencil mask 14 is formed of a silicon substrate andslit-shaped patterning openings 14 a to form resist patterns.

[0300] The heat absorption mask 16 is formed of a silicon substratecoated with an SiN film and provided with openings 16 a formed in almostthe same pattern as the patterning openings 14 a of the stencil mask 14.The opening 16 a is formed in such a size as to prevent electron beamsnecessary to form resist patterns from being blocked. That is, the sizeof the opening 16 a is the same as the size of the patterning opening 14a or the size of the opening 16 a is a little larger.

[0301] Both the silicon plates 11 and 15 have a large opening. The largeopening of the silicon plate 11 is provided in the area of the uppersurface of the stencil mask 14 in which the patterning openings 14 a areformed. On the other hand, the large opening of the silicon plate 15 isprovided in the area of the upper surface of the heat absorption mask 16in which the openings 16 a are formed. The silicon plates 11 and 15provide space between the stencil mask 14 and the heat absorption mask16 and between the two heat absorption masks 16.

[0302] The metal cover 22 is formed of a tungsten substrate and providedwith an opening 22 a. As shown in FIG. 21, the opening 22 a is largerthan the opening 16 a of the heat absorption mask 16 so that the metalcover 22 does not block the opening 16 a of the heat absorption mask 16.

[0303] The size of the concave section 21 a of the frame 21 is almostthe same as that of the stencil mask 14, silicon plate 11, heatabsorption mask 16, silicon plate 15 and metal cover 22. Furthermore, alarge opening 21c is provided inside the concave section 21 a and thelarge opening 21 c exposes the area of the under surface of the stencilmask 14 in which the patterning openings 14 a are formed.

[0304] In the multi-layer structured exposure mask 1F of thisembodiment, the patterning openings 14 a of the stencil mask 14, theopenings 16 a of the heat absorption mask 16 and the opening 22 a of themetal cover 22 are aligned in the horizontal direction as shown in FIG.21.

[0305] The multi-layer structured exposure mask 1F of this embodiment isset with the frame 21 facing the electron gun 31 side of the EB exposureapparatus 100 as in the case of the multi-layer structured exposure mask1 of Embodiment 1. At this time, electron beams that have passed throughthe openings 16 a pass through the patterning openings 14 a.

[0306] As is apparent from the explanations, the multi-layer structuredexposure mask 1F of this embodiment has almost the same structure asthat of the multi-layer structured exposure mask 1E of Embodiment 6.However, this embodiment is different from the multi-layer structuredexposure mask 1E of Embodiment 6 in that the metal cover 22 is provided.

[0307] As in the case of the multi-layer structured exposure mask 1E ofEmbodiment 6, the multi-layer structured exposure mask 1F of thisembodiment is provided with the heat absorption mask 16. This allowssuppression of deformation of the stencil mask 14 due to thermalexpansion and more accurate formation of resist patterns similarly asthe multi-layer structured exposure mask 1E of Embodiment 6 at all.Especially this embodiment provides the metal cover 22 that blocks mostof electron beams that do not pass through the openings 16 a andpatterning openings 14 a. This reduces electron beams irradiated ontothe heat absorption masks 16 and stencil mask 14 placed below the metalcover 22. Therefore, deformation due to heat generation in the heatabsorption masks 16 and stencil mask 14 is suppressed. This makes itpossible to form a resist pattern that reflects the shapes of thepatterning openings 14 a more accurately.

[0308] Furthermore, the heat absorption masks 16 are separated from thestencil mask 14 by the hollow section 11 a and do not directly contacteach other. Because of this, the heat generated in the heat absorptionmasks 16 is mostly not transmitted to the stencil mask 14 but dissipatedto the outside through the silicon plate 15 and frame 20. Thissuppresses or prevents deformation of the stencil mask 14.

[0309] Furthermore, the size of the concave section 21 a of thisembodiment is almost the same as the sizes of the silicon plate 11,stencil mask 14, silicon plate 15 and the heat absorption masks 16, andthe silicon plate 15 and the heat absorption masks 16 are fitted in theconcave section 21 a. For this reason, the silicon plate 15 and the heatabsorption mask 16 are securely fixed. This allows more accuratealignment between the patterning openings 14 a and the openings 16 a.

[0310] By the way, the modification example described in Embodiment 1 isalso applicable to the multi-layer structured exposure mask 1F of thisembodiment and the same effect can also be obtained by the modificationthereof.

Manufacturing Method

[0311] Then, the method for manufacturing the multi-layer structuredexposure mask 1F of this embodiment will be explained with reference toFIG. 22. FIG. 22 is a process cross-sectional view showing the methodfor manufacturing the multi-layer structured exposure mask 1F accordingto this embodiment.

[0312] First, in the process shown in FIG. 22(a), the silicon plate 11having a large opening and the stencil mask 14 provided with thepatterning openings 14 a are prepared. More specifically, a siliconplate 11 on the under surface of which a silicon oxide film is formed isprepared first and a stencil mask plate (Si film) is formed on thesilicon oxide film using a CVD method, etc. Then, the stencil mask 14 isformed by forming patterning openings 14 a that penetrate the stencilmask plate. Then, a large opening is formed in the silicon plate 11 insuch a way as to expose the patterning openings 14 a of the stencil mask14.

[0313] Then, the frame 21 made of glass and having a concave section 21a almost as large as the stencil mask 14 and having a large opening 21 cin the concave section 21 a is prepared. Then, the stencil mask 14 onthe upper surface of which the silicon plate 11 is provided is fitted inthe concave section 21 a. At this time, the under surface of the stencilmask 14 is pasted to the bottom face of the concave section 21 a.

[0314] Then, in the process shown in FIG. 22(b), the silicon plate 15provided with a large opening almost as large as the large opening 21 cof the frame 21 and the heat absorption mask plate 16′ are prepared.More specifically, the heat absorption mask plate 16′ (SiN film) isformed on the under surface of the silicon plate 15 using a CVD method,etc. Then, a large opening is formed in the silicon plate 15 in such away as to expose the upper surface of the heat absorption mask plate16′.

[0315] Then, the resist 17 is formed on the upper surface of the heatabsorption mask plate 16′ exposed in the large opening of the siliconplate 15.

[0316] Then, the silicon plate 15 is pasted to the under surface of theframe 21. At this time, alignment is performed in such a way that thelarge opening 21 c of the frame 21 matches the large opening of thesilicon plate 15. X-rays are irradiated through the stencil mask 14 andthe resist 17 is subject to a photoreaction in a self-aligning way.Then, the resist 17 is developed to form resist openings 17 a.

[0317] By the way, in this process, it is also possible to form theresist 17 on the upper surface of the heat absorption mask plate 16′after pasting the under surface of the frame 20 to the upper surface ofthe silicon plate 15.

[0318] This embodiment repeats the process shown in FIG. 22(b) threetimes.

[0319] Then, in the process shown in FIG. 22(c), the heat absorptionmask plates 16′ provided with the three patterned resists 17 obtained inthe process shown in FIG. 22(b) are fitted in the concave section 21 aof the frame 21.

[0320] Then, in the process shown in FIG. 22(d), dry etching is appliedusing the resist 17 in which the resist opening 17 a is formed as themask to form three heat absorption masks 16 having openings 16 a formedin almost the same pattern as the pattering openings 14 a.

[0321] Then, in the process shown in FIG. 22(e), the metal cover 22formed of a tungsten substrate and provided with openings 22 a arefitted in. At this time, the openings 22 a are aligned in such a waythat the metal cover 22 does not block the openings 16 a of the heatabsorption mask 16.

[0322] In the processes, the multi-layer structured exposure mask 1F ofthis embodiment is obtained.

[0323] According to this method, the heat absorption mask 16 is formedbased on the stencil mask 14, and therefore there is no need to alignthe openings 16 a of the heat absorption mask 16 and the patterningopenings 14 a of the stencil mask 14. Furthermore, the stencil mask 14and the heat absorption masks 16 are fitted in the concave section 21 aand fixed according to this method, and therefore there is littlepossibility that there will be a positional difference between theopenings 16 a and patterning openings 14 a. That is, this methodprovides the multi-layer structured exposure mask 1F in which theopenings 16 a match the patterning openings 14 a with high accuracy.

[0324] Furthermore, in the process shown in FIG. 22(b), it is alsopossible to apply dry etching using the resist 17 in which the resistopenings 17 a are formed as the mask to form the heat absorption mask16, and fit the heat absorption mask 16 obtained in the process shown inFIG. 22(b) into the concave section 21 a of the frame 21 in the processshown in FIG. 22(c) and remove the resist 17 in the process shown inFIG. 22(d).

[0325] This method uses either an anode junction or an adhesive as atechnique for pasting the frame 21, metal cover 22, silicon plates 15,heat absorption masks 16, silicon plate 11 and stencil mask 14 to eachother.

Modification Example

[0326] As shown above, this embodiment has described the exposure maskfor an electron beam exposure apparatus, but it is also possible toprovide the exposure mask for an X-ray exposure apparatus by providing alaminated film with an X-ray shielding metal film provided with amembrane and patterning openings instead of the stencil mask 14.

[0327] Moreover, this embodiment has a configuration with three heatabsorption masks 16, but only with at least one heat absorption mask 16this embodiment can display a heat absorption effect.

[0328] This embodiment has used the metal cover 22 formed of a tungstensubstrate, but the present invention is not limited to this and amaterial with high thermal conductivity can be used. Examples of thematerial with high thermal conductivity include a molybdenum substrate,etc.

Exposure method Using a plurality of Exposure Masks

[0329] The multi-layer structured exposure masks described in theforegoing embodiments are ideally applicable to an exposure method usinga plurality of exposure masks. Here, a case where a resist is patternedusing two exposure masks having complementary patterning openings willbe explained with reference to FIGS. 23(a) and 23(b). FIG. 23(a) is atop view showing the multi-layer structured exposure mask 1 ofEmbodiment 1 and FIG. 23(b) shows a multi-layer structured exposure mask1′ which is different from the multi-layer structured exposure mask 1 ofEmbodiment 1 only in the pattern of the openings 16 a (patterningopenings 14 a).

[0330] As shown in FIGS. 23(a) and 23(b), the area in which the openings16 a (openings 14 a) of the multi-layer structured exposure mask 1′ areformed is smaller than the area of the multi-layer structured exposuremask 1 shown in FIG. 23(a). That is, the opening ratio of the heatabsorption mask 16 (stencil mask 14) of the multi-layer structuredexposure mask 1′ is smaller than that of the multi-layer structuredexposure mask 1.

[0331] In the case of the conventional electron beams exposure mask,there is a difference in the amount of heat generation between anexposure mask with a large area blocking electron beams (small openingratio) and an exposure mask with a small area blocking electron beams(large opening ratio). Thus, deformation due to heat generation alsodiffers. Therefore, even if the openings of the two exposure masks arealigned, a positional difference is produced due to the difference indeformation due to heat generation. Thus, using a mask of a differentopening ratio involves a problem of a large positional difference.

[0332] On the other hand, the multi-layer structured exposure masks 1and 1′ differ in the amount of heat generation at the heat absorptionmask 16 with a small opening ratio (that is, having a large areablocking electron beams). However, as explained in Embodiment 1,deformation of the pattering mask 14 due to heat generation issuppressed with the multi-layer structured exposure masks 1 and 1′,which suppresses a positional difference.

[0333] That is, using the multi-layer structured exposure masks of therespective embodiments having a heat absorption mask makes it possibleto avoid influences of heat even if the two multi-layer structuredexposure masks have different opening ratios and form accurate resistpatterns.

Alignment Method

[0334] Then, alignment among a plurality of exposure masks according tothe exposure method using a plurality of multi-layer structured exposuremasks will be explained with reference to FIG. 23 and FIG. 24. FIG. 24is an enlarged view of the alignment openings formed in the multi-layerstructured exposure masks 1 and 1′.

[0335] As shown in FIG. 23(a) and FIG. 23(b), an alignment opening 16 pis formed in the peripheral area of the heat absorption mask 16 of themulti-layer structured exposure masks 1 and 1′. Right below thealignment opening 16 p, an alignment opening 14 p is formed in theperipheral area of the stencil mask 14 as shown in FIG. 24(a). FIG.24(b) and 24(c) show the alignment openings 16 p and 14 p formed in theheat absorption mask 16 and stencil mask 14 respectively and FIG. 24(a)is a top view corresponding to a state in which the heat absorption mask16 is superimposed on the stencil mask 14 (that is, a top view of theperipheral area of the multi-layer structured exposure mask 1 or 1′).

[0336] When exposure is carried out using the multi-layer structuredexposure mask 1 (hereinafter referred to as “first mask”) shown in FIG.23(a), and then exposure is carried out using the multi-layer structuredexposure mask 1′ (hereinafter referred to as “second mask”) shown inFIG. 23(b), the first mask is aligned with the second mask using a He—Nelaser, etc. A laser is irradiated onto the alignment opening 14 p formedin the stencil mask 14 for alignment, but the amount of heat generationof the stencil mask 14 by laser irradiation is extremely small.Therefore, there is no need to block the laser beam with the heatabsorption mask 16. Thus, the alignment opening 16 p is made largeenough to allow the laser beam to pass through. The alignment opening 16p can be arbitrarily shaped so as not to block the alignment opening 14p (for example, a square shape including the alignment opening 14 p asshown in FIG. 24(a)).

[0337] Here, the multi-layer structured exposure mask of Embodiment 1 isused in this explanation as an example, but it is also possible toprovide the alignment openings 14 p and 16 p in the multi-layerstructured exposure masks according to Embodiment 3, Embodiment 5 to 7.However, in the case of the multi-layer structured exposure mask 1F ofEmbodiment 7, it is possible to form an alignment opening in the metalcover 22 in an arbitrary shape that will not block the alignmentopenings 14 p and 16 p.

[0338] Furthermore, in the case of the multi-layer structured exposuremasks for X-ray exposure according to Embodiments 2 and 4, the alignmentopening 13 p is formed right below the alignment opening 16 p in theperipheral area of the X-ray shielding metal film 13 as shown in FIG.25. The laser used for alignment is a laser of a wavelength thatpenetrates the membrane 12.

Industrial Applicability

[0339] The exposure mask of the present invention is used for anexposure apparatus using an exposure light source such as chargedparticle beams and X-rays.

What is claimed is:
 1. An exposure mask, comprising: a patterning maskhaving an opening; and at least one heat absorption mask having anopening and placed above the patterning mask apart from the patterningmask, and the opening of the patterning mask is aligned with the openingof the heat absorption mask.
 2. The exposure mask according to claim 1,wherein the opening of the heat absorption mask is greater than or aslarge as the opening of the patterning mask.
 3. The exposure maskaccording to claim 1, wherein the openings of the heat absorption maskand the patterning mask are slit-shaped, and the opening of the heatabsorption mask is wider than or as wide as the opening of thepatterning mask.
 4. The exposure mask according to any one of claim 1 toclaim 3, wherein the thermal conductivity of the heat absorption mask isgreater than that of the patterning mask.
 5. The exposure mask accordingto any one of claim 1 to claim 4, wherein a plurality of the heatabsorption masks are provided, and the openings of the respective heatabsorption masks are aligned with the openings of the patterning mask.6. The exposure mask according to any one of claim 1 to claim 5, whereinthe thickness of the heat absorption mask is greater than the thicknessof the patterning mask.
 7. The exposure mask according to any one ofclaim 1 to claim 6, wherein the patterning mask and the heat absorptionmask are made of the same material.
 8. The exposure mask according toany one of claim 1 to claim 7, further comprising a metal cover havingan opening larger than the opening of the heat absorption mask, whereinthe metal cover is placed above the heat absorption mask.
 9. Theexposure mask according to any one of claim 1 to claim 8, wherein analignment opening is formed in the patterning mask, and an opening in ashape different from the alignment opening and larger than the alignmentopening is formed in an area of the heat absorption mask located rightabove the alignment opening.
 10. The exposure mask according to any oneof claim 1 to claim 9, further comprising a support for supporting theedges of the patterning mask and the heat absorption mask, wherein boththe patterning mask and the heat absorption mask are placed either aboveor below the support.
 11. The exposure mask according to any one ofclaim 1 to claim 9, further comprising a support for supporting theedges of the patterning mask and the heat absorption mask, wherein thepatterning mask and the heat absorption mask are placed in such a waythat the support is inserted between the patterning mask and the heatabsorption mask.
 12. The exposure mask according to claim 10 or claim11, wherein the support further comprises a concave section, and theheat absorption mask is engaged with the concave section and ispositioned in the concave section.
 13. The exposure mask according toclaim 10 or claim 11, wherein the support further comprises a concavesection, and the patterning mask is engaged with the concave section andis positioned in the concave section.
 14. The exposure mask according toany one of claim 1 to claim 13, wherein there exists a hollow sectionbetween the patterning mask and the heat absorption mask formed byetching of a member between the patterning mask and the heat absorptionmask.
 15. The exposure mask according to any one of claim 1 to claim 14,wherein a membrane is provided on the upper surface of the patterningmask.
 16. An exposure method for irradiating charged particles using anexposure mask comprising a patterning mask having an opening and atleast one heat absorption mask having an opening and placed above thepatterning mask apart from the patterning mask with the opening of thepatterning mask aligned with the opening of the heat absorption mask,wherein the charged particles are irradiated at an acceleration voltageof 10 keV or above.
 17. The exposure method according to claim 16,wherein the charged particles are irradiated at an acceleration voltageof 50 keV or above.
 18. The exposure method according to claim 16 orclaim 17, wherein another exposure mask is used which has a patterningmask having an opening and at least one heat absorption mask having anopening and placed above the patterning mask apart from the patterningmask with the opening of the patterning mask aligned with the opening ofthe heat absorption mask, and the opening pattern of the patterning maskof the exposure mask is different from the opening pattern of thepatterning mask of the other exposure mask.
 19. An exposure method forirradiating X-rays using an exposure mask comprising a patterning maskhaving an opening, at least one heat absorption mask having an openingand placed above the patterning mask apart from the patterning mask anda membrane for supporting the pattering mask, with the opening of thepatterning mask aligned with the opening of the heat absorption mask,wherein the patterning mask is formed of such a material as to preventX-rays from penetrating.
 20. The exposure method according to claim 18,wherein the X-rays are SOR-X-rays.
 21. The exposure method according toclaim 19 or 20, wherein another exposure mask is used which has apatterning mask having an opening, at least one heat absorption maskhaving an opening and placed above the patterning mask apart from thepatterning mask and a membrane for supporting the pattering mask, withthe opening of the patterning mask aligned with the opening of the heatabsorption mask and with the patterning mask formed of such a materialas to prevent X-rays from penetrating, and the opening pattern of thepatterning mask of the exposure mask is different from the openingpattern of the patterning mask of the other exposure mask.
 22. Anexposure mask manufacturing method, comprising: a step (a) of preparinga patterning mask having an opening and a heat absorption mask having anopening in almost the same pattern as the opening pattern of thepatterning mask; and a step (b) of aligning the opening of thepatterning mask with the opening of the heat absorption mask.
 23. Theexposure mask manufacturing method according to claim 22, wherein thepatterning mask is formed of a laminated film with a membrane and X-rayshielding material.
 24. An exposure mask manufacturing method,characterized by comprising: a step (a) of preparing a heat absorptionmask having an opening; a step (b) of placing a patterning masksubstrate below the heat absorption mask; a step (c) of stacking aresist on the under surface of the patterning mask substrate; a step (d)of patterning the resist by irradiating radiation penetrating thepatterning mask substrate onto the resist using the heat absorption maskas the mask; and a step (e) of forming a patterning mask having anopening by etching the patterning mask substrate using the resist as themask.
 25. The exposure mask manufacturing method according to claim 24,wherein in the step (b), a support is inserted between the heatabsorption mask and the patterning mask substrate.
 26. An exposure maskmanufacturing method, comprising: a step (a) of preparing a heatabsorption mask having an opening; a step (b) of providing a plate onthe under surface of the heat absorption mask; a step (c) of providingthe patterning mask substrate on the under surface of the plate; a step(d) of forming a patterning mask having an opening by etching the plateand the patterning mask substrate using the heat absorption mask as themask; and a step (e) of removing a part of the plate located in an areain which the openings of the heat absorption mask and patterning maskare formed.
 27. The exposure mask manufacturing method according toclaim 26, wherein in the step (e), the material making up the plate hasa higher etching speed than the heat absorption mask and the patterningmask substrate.
 28. An exposure mask manufacturing method, comprising: astep (a) of placing a heat absorption mask having an opening above thepatterning mask substrate on the upper surface of which a resist isformed; a step (b) of patterning the resist using the heat absorptionmask as the mask; and a step (c) of forming a patterning mask having anopening by etching the patterning mask substrate using the resist as themask.
 29. The exposure mask manufacturing method according to claim 28,wherein in the step (a), the heat absorption mask is placed above thepatterning mask substrate after a resist is formed on the upper surfaceof the patterning mask substrate.
 30. The exposure mask manufacturingmethod according to claim 28, wherein in the step (a), the patterningmask substrate on the upper surface of which a resist is formedbeforehand is placed below the heat absorption mask after the heatabsorption mask is placed.
 31. The exposure mask manufacturing methodaccording to any one of claim 28 to 30, wherein in the step (a), asupport is placed to support the edges of the patterning mask substrateand the heat absorption mask and the heat absorption mask is engagedwith the support.
 32. An exposure mask manufacturing method, comprising:a step (a) of placing a patterning mask having an opening above a heatabsorption mask substrate on the upper surface of which a resist isformed; a step (b) of patterning the resist using the patterning mask asthe mask; a step (c) of placing the heat absorption mask substrate abovethe patterning mask; and a step (d) of forming a heat absorption maskhaving an opening by etching the heat absorption mask substrate usingthe resist as the mask.
 33. The exposure mask manufacturing methodaccording to claim 32, wherein in the step (a), the patterning mask isplaced above the heat absorption mask substrate after the resist isformed on the upper surface of the heat absorption mask substrate. 34.The exposure mask manufacturing method according to claim 32, wherein inthe step (a), the heat absorption mask substrate on the upper surface ofwhich the resist is formed beforehand is placed below the patterningmask after the patterning mask is placed.
 35. The exposure maskmanufacturing method according to any one of claim 32 to 34, wherein inthe step (a), a support is placed to support the edges of the patterningmask and the heat absorption mask substrate, the patterning mask isengaged with the support, and in the step (c), the heat absorption masksubstrate is engaged with the support.
 36. The exposure maskmanufacturing method according to claim 32 to claim 35, wherein the step(b) and step (c) are repeated.
 37. The exposure mask manufacturingmethod according to any one of claim 32 to claim 36, wherein a step (f)of placing a metal cover having an opening larger than the opening ofthe heat absorption mask above the heat absorption mask is furtherincluded after the step (d).
 38. An exposure mask manufacturing method,comprising: a step (a) of placing a patterning mask having an openingabove the heat absorption mask substrate on the upper surface of which aresist is formed; a step (b) of patterning the resist using thepatterning mask as the mask; a step (c) of forming a heat absorptionmask having an opening by etching the heat absorption mask substrateusing the resist as the mask; and a step (d) of placing the heatabsorption mask above the patterning mask.
 39. The exposure maskmanufacturing method according to claim 38, wherein in the step (a), thepatterning mask is placed above the heat absorption mask substrate afterthe resist is formed on the upper surface of the heat absorption masksubstrate.
 40. The exposure mask manufacturing method according to claim38, wherein in the step (a), the heat absorption mask substrate on theupper surface of which a resist is formed beforehand is placed below thepatterning mask after the patterning mask is placed.
 41. The exposuremask manufacturing method according to any one of claim 38 to 40,wherein in the step (a), a support is placed to support the edges of thepatterning mask and the heat absorption mask substrate, the patterningmask is engaged with in the support, and in the step (d), the heatabsorption mask is engaged with in the support.
 42. The exposure maskmanufacturing method according to claim 38 to claim 41, wherein the step(b) and step (c) are repeated.
 43. The exposure mask manufacturingmethod according to any one of claim 38 to 42, wherein a step (f) ofplacing a metal cover having an opening larger than the opening of theheat absorption mask above the heat absorption mask is further includedafter the step (d).